Suggestions re Munich - Berlin - Frankfort trip for June

-should we train from Munich to Nurnberg, spend the night there and then train on to Berlin?

Yes. Flying from Berlin to Munich does not make sense in your case (with Munich airport being far outside the city centre). Considering airport transfer and waiting times, the fastest train connections are about as fast as the flight. And they go via Nürnberg / Nuremberg. With the opportunity for a stopover (possibly on the same ticket) by train, the flight is a worse option. It can be cheaper than the train, but probably not if you take into account the extra cost you'd have for a day trip to Nuremberg.

• is it worth trying to squeeze in Rothenburg?

I don't think so. There is nothing wrong with Rothenburg, but I'd want to minimize time in transit and maximize time spent at worthwhile destinations. Rothenburg is worthwhile, but so is Nuremberg (and Bamberg, and Erfurt, ...).

should we train from Berlin or fly from Berlin to Frankfurt?

Compare prices. Depending on your risk aversion (how early to arrive at the airport) and whether you have check-in luggage, you might save up to an hour by flying compared to the train. Not really worth it if you have to pay more, but sometimes, flying is actually cheaper.

Spend the night around Frankfurt airport

Note that the city centre is very close to the airport and well-connected by public transport. You need more time to get to the airport from many "airport" hotels than from the central train station (which has lots of hotels nearby).

Day 11 (Sunday) - Day 13 (Tuesday): Black Forest

What do you expect to see? I am asking because there might be alternatives closer to Frankfurt or your route.

"Can we combine Eagles Nest and Saltzburg in one day?"

No, but these are so close to each other and far from München that it would make sense to combine them into a 2 day trip, with a night's stay at Salzburg or Berchtesgaden. This would save you lot's of travelling back and forth.

Here is a good info about the daytrip to Füssen(for Neuschwanstein): https://blog.rail.cc/neuschwanstein-munich-fussen-train/

"should we train from Munich to Nurnberg, spend the night there and then train on to Berlin?"

That's the best way to do it.

"is it worth trying to squeeze in Rothenburg?"

No, it's not practical and Rothenburg is a tourist trip. If you want to squeeze in a small town, than try something closer to Nürnberg or between Nürnberg and Berlin, for example Bamberg, Naumburg.

"should we train from Berlin or fly from Berlin to Frankfurt? Trying not to spend too much money"

Train. To save money you can:

A) Book tickets ASAP, you may still find affordable tickets if you're flexible with the departure time.

B) Book tickets on Flixtrain, a private railway, which has only a couple of trains, but it is usually much cheaper than DB.

https://www.flixtrain.com/

C) Take unreserved regional trains, it's much slower than the direct high-speed train(around 9 hours instead of 4) and you have to change trains at least 3 times, but it costs only 60€ for the 3 of you, or 52€ if the teen is under 15.

https://www.bahn.com/en/view/offers/regional/day-ticket-for-germany.shtml

Berlin- Checkpoint Charlie is a reproduction, actors in costumes. Not worth your time.
There are so many other amazing places to see in Berlin.

I love Berlin. There is so much to see there. You may not have time for my suggestions, but I'll offer a few.

There are greenspaces, gardens, and parks everywhere in Berlin. Some of my favorite outdoor places...

• The Tiergarten, of course, is right in the city of the center and has a variety of areas worth seeing. I am particularly fond of the Luiseninsel.
  
• Volkspark Friedrichshain is a favorite park of mine. It has a fairy tale fountain, playgrounds, two hills made from WWII rubble, numerous recreation areas, a memorial to Polish Soldiers and German Anti-fascists. It's a great place to watch Berliners being Berliners.
• Britzer Garten was recommended to me by one of my German Skype tutors who lived in Berlin. It's a nice outdoor space on the south side of the city that provides a nice escape from the city. The roses should be in bloom around the time you are there. I've only been in the spring when the tulips/rhododendrons are in bloom, but I would expect it to be great any time.
• Gärten der Welt (Gardens of the World) is on the east side of Berlin and features gardens that reflect gardening styles from around the world

For architecture ideas, see the places I listed in this post: https://community.ricksteves.com/travel-forum/germany/which-city

I tend to agree with Suki on Checkpoint Charlie. There is nothing less authentic and more touristy in Berlin than the current iteration of Checkpoint Charlie. It's totally skippable UNLESS you want to see the intersection where history happened (e.g., tanks pointed at each other), recognizing that there is little there (other than a few placards hanging on a temporary wall) to indicate that anything meaningful happened there.

For Berlin, do at least one good walking tour and you will see all the top sites as well as learn some of the history. My go-to tour company is Insider Tours.
Would also do a walking tour in Munich. So much better than a hoho bus. Not sure? Read reviews on Trip Advisor. No one ever raves about their hoho bus tour. You spent a lot of money to get to Europe, and the best way to see the cities here are usually on foot.

Do NOT stay near the airport in Frankfurt. The city is only 11 km. away from the airport. There is nothing out there to see, no restaurants, nix. In the city, you have a huge choice of hotels for any budget, and you are close to great restaurants and great sightseeing. Trains to the airport run every 15 min. and only take 11 min. from the central station.

Rather than Rothenburg, you could visit Büdingen, Marburg, Limburg, Seligenstatdt, Idstein, Gelnhausen, Michelstadt. All within a 1-hour train ride from Frankfurt.

Check the Deutsche Bahn website for train ticket prices. Add in what it costs you to get to and from the airport when comparing trains to planes, plus the time involved. I lean towards taking the train. Start in the middle of the city and end in the middle of the city. 4-hour train ride.

In my opinion in Berlin it is useless to compare a HoHo bus tour with a walking tour because the focus and range is totally different. To get a feeling for the city a HoHo bus tour makes more sense. A walking tour - company does not matter - has always a specific focus, very often the genral ones lead from Brandenburg Gate to Alexanderplatz or Hackescher Markt - or vice versa. I recommend to do a HoHo bus tour in the afternoon of arrival day and a walking tour the morning of first full day in town.

Have also a look at top 10 from VisitBerlin: If you are already at Brandenburg Gate walk over to Reichstag. For visiting the Reichtag building from inside you need to pre-register to avoid waiting in lanes.

I agree that Checkpoint Charlie became a lowlight because even if the place of the small house is the same, all the stuff around is fake. The large information boards on right side of Friedrichstrasse heading North are worth reading.

If architecture is your focus I recommend to visit the places of Cold War architecture. Also interesting is the New Berlin Palace which tries to combine classic and new architecture styles. Classic architecture and a wonderful park you will find at Charlottenburg Palace (stop of some HoHo bus tours by the way). Also visit the New Wing from inside.

No need to take a Ho-Ho bus tour in Berlin, the public bus no. 100 is just as good and doesn't need extra ticket if you already have a transit pass.

https://www.visitberlin.de/en/explore-berlin-bus-100

Bus 100 and not to forget bus 200 have no comments, it is just regular public transport. So you will not know what you see when you did not study a guide before. Also the route is only a very small part of a typical HoHo bus tour, and also in some parts bues 100 and 200 just drive by a street away, you will miss beautiful places such as Gendarmenmarkt and some others.

Just compare the maps:

• Public bus 100 & 200 routes
• HoHo bus tour example (red line), other routes include western city and Charlottenburg Palace

The time we spent waiting on over-full buses 100 and 200 until one came that had space for us, (2 people) was extensive. Then the bus sits in traffic jams, over and over. If you are not in the front with the big windows, you seriously see nothing. We felt this was the biggest waste of our short 2 days in Berlin. I do not understand why this is a thing to do in Berlin? We did it cause it was recommended on this forum.

https://www.annees-de-pelerinage.com/art-nouveau-walking-tour-munich/ this site has some suggested walks in Munich neighborhoods with some nice older homes. Am planning on doing them this September.

Such great suggestions!! Thanks so much. Welcome any additional info!

If you're interested in the Berlin Wall, rather than going to Checkpoint Charlie, go to the Berlin Wall exhibits in the Nordbahnhof and nearby Bernauer Strasse (details in Rick's book). This is the only section where the double wall construction is still intact, and you can watch videos about the wall too. As a bonus, it's free.

For more things to see and do in Berlin, here's an interesting thread; note that each of us who responded had different "must sees" and "favorites," as there is such a depth and breadth of sights. https://community.ricksteves.com/travel-forum/germany/what-not-to-miss-in-berlin

Yes, the Berlin Wall Memorial (Gedenkstätte Berliner Mauer) on Bernauer Straße is excellent and lets you see the wall as it existed. It's a far, far better place to visit than Checkpoint Charlie. Watch the videos in the visitor/exhibition center. They always make me tearful in a happy way.

For a more obscure Berlin Wall site... go to the location of the old Bornholmer Straße crossing at Bösebrücke (a bridge that stands at the old East/West Berlin border). This was the first crossing to open on Nov 9, 1989 (nice NPR story here: https://www.npr.org/sections/parallels/2014/11/06/361785478/the-man-who-disobeyed-his-boss-and-opened-the-berlin-wall). There is still a remnant of the Wall there, along with some signs that recount the history. The border crossing station is long gone -- replaced by a Lidl grocery store. The last time I was there, there was still a small patch of asphalt with some faded lane markings that had run from the bridge to the crossing station.

For three people, rent a car will probably save a lot of $$$ and its more efficient than train/bus. I timed out train vs car the other day in a dispute with a defender of train travel, and taking the train for the day trip in question took at least 3 times longer than car.

Baroque churches are my favorite thing to see in Bavaria. There are some second rate ones in Munich and about 4 outstanding ones between Muinch and Fussen (that was a day trip by car). And there is a spectacular one by the Assam brothers between Passau & Regensbung.

On the Romantic Road, include Nordlingen, an uncrowded version of Rothenburg o.d.T. Consider the Bavarian part of the Deutschalpinestrasse (German Alpine Road). Must have: Michelin Green Guide-- Germany.

Berlin ranks high on my list of places I wish I never went to. In WWII, the Red Army blew Berlin off the fare of the Earth, and Berlin rebuilt in cheap, boring, boring, boring 1950s modern architecture. A car will save your trip. Head upstream along the Elbe to Wurtenburg, Meissen, Dresden, & Torgau (never heard of it? Torgau has 500 surviving medieval buildings and a castle.

Frankfurt days-- Rhine Gorge & Mosel Valley.

On "trying to squeeze in Rothenburg?"...My opinion absolutely not. Spend that extra time in Berlin. As has been suggested, I would skip Checkpoint Charlie also.

Other interesting areas in Berlin to explore, visit...Spandau, Köpenick, Mitte from the Brandenburg Gate to Jannowitzbrücke. Go to the Nikolai Viertel...a lot of walking here where you'll see the Berliner Dom, Bebelplatz, Neue Wache, Unter den Linden, the statue of Frederick the Great (Reiterdenkmal), Museum Island, Berliner Rathaus, Alexanderplatz.

Any specific historical interests in Berlin? If so, I would focus your efforts east of the Brandenburg Gate, ie stay mainly in the eastern area.

Specific interests would be interesting neighborhoods in addition to the items noted above. Son interested in WWII so possibly a a museum or other historical site.

For three people, rent a car will probably save a lot of $$$ and its more efficient than train/bus. I timed out train vs car the other day in a dispute with a defender of train travel, and taking the train for the day trip in question took at least 3 times longer than car.

I don't think there is a general answer to that debate. In my opinion, a car makes sense for regional day trips to rural areas. To travel between cities, the train usually makes more sense. An extreme exampe: Going from Karlsruhe to Paris by car takes 5 1/2 hours under ideal conditions, with little traffic and no breaks. By train, this takes 2 1/2 hours, and you can read a book during the journey. Berlin to Munich is less extreme, but also faster by train than by car. And a long-distance train is just so much more comfortable than a car...