Car vs train vs bus

I lived in Germany for 4 years found that driving in Germany is not difficult for Americans. Germans do follow the traffic rules.
Note, however, driving on the autobahns that in some areas have unlimited speeds, can be a bit scary at first.

When on the autobahns, you must move into the right line when a vehicle approaches you from the rear at a speed higher than yours. If you don't move over, you have violated their right of way. In the USA, many Americans tend to hog the left lanes of the interstate. DO NOT DO this in Germany.

Also, gasoline is about double the cost in Germany compared to the US.
Still, you should consider renting a car if you are away from a large city and want to see the countryside. Going to places that you mentioned can be appreciated better by driving the countryside. Still, if you are in Frankfurt or Munich, you don't want to pay for parking and deal with heavy traffic.

The trains are great in Germany and save $$$ by going second class.

Also, with three of you, you wlll save by driving instead of paying for three rail tickets.

Map out your itinerary and if you are planning to be in a large city, consider where you lodge and if it has parking. Still, for the places you mentioned a car is best.

I always go to Kayak.com to check prices for lodging and rental cars. Then I go directly to the source and book the car rental. Be sure to rent a car with enough trunk space for your luggage.

It depends. Start by finding out where you want to go, then you can find the best way to get there. A car can be useful in some areas, but probably won't save you money compared to e.g. the Länder-tickets that are very good value if you are a group.

Assuming visitors to Germany will be able to buy the pass— and this has not yet been announced— the 2023 Deutschland Ticket covering all regional trains, public buses, U-bahns, S-Bahns and trams throughout Germany could be the way to go.
The Digital Deutschland ticket ( D-Ticket) will cost €49 per calendar month and cover travel on all local trains ( not the fastest IC, ICE, or EC trains) for one month in Germany beginning on May 1. The only caveat is that it has not yet been announced if visitors to Germany will be able to buy the pass. The pass is a digital subscription that needs to be activated by the 19th of the month before the month you need it. In other words, if your trip is from June 5-25, you will want to subscribe by May 19 for the D-Ticket to be valid from June 1-30. It is a subscription enrollment which should be cancelled the day after you subscribe so you are not billed monthly for the remaining months of 2023.
BVG, Berlin’s Transit Authority, is the site for signing up for a Deutschland Ticket. www.bvg.de/en
Have a great Trip!

It depends most places in Germany that aren't too rural have great public transport and definitely are more relaxing than driving. Also keep in mind that petrol or Benzin as the Germans call it costs a lot more than in the US.

I would suggest that you stick with trains for the most part (especially from city to city). But if you're in an area where public transportation is cumbersome, you might want to rent a car for a few days.

I did that last year in Germany - I was there for a month and used trains all over the country. But I was one part of the country (Ostbevern in North Rhine-Westphalia) where bus and train travel was more difficult, so I rented a car for 4 days from Müenster airport. It's easy and relatively inexpensive. I rented my car from AutoEurope, which is a consolidator for various agencies. I think the rental car came from Sixt.

Should we only use trains or mix rental car , busses, and trains.

I would agree with Mardee. Use trains and buses as much as possible, but be open to cars only if you cannot get to where you want to go with public transportation. That has been my travel philosophy since 2000, and I actually have never had to resort to renting a car (almost did once, but considering the cost of a one day rental, I chose to go to a different venue, one I could get to using public transportation).

For past trip, I have usually done a study after returning on what I spent for train and bus tickets versus what it would have cost me for a rental car for the same time span, and using public transportation has always turned out to be half to a third of what a car rental would cost.

For instance, in 2019 we (2) made a 20 day trip to Germany, flying into FRA and starting in St. Goar, going to Pfronten (near Füssen, then Lindau, then Rothenburg, ending up in a small town on the Main river between Würzburg and Frankfurt, from which we made side trips, then flying out of FRA. Using a combination of local tickets, regional passes, and one Sparpreis ticket, we spent 267€, approx $287 at todays exchange rate. Even assuming 3 people at todays exchange rate and some new fares, it would have cost $420. I got some quotes for renting a car big enough for three people that I wouldn't mind driving on the autobahn, without CDW (which I would never do), of almost $800 for the three week trip.

In the Rhein valley, there are train lines (and highways) on either side of the river. Easy to get from town to town.

In the Black Forest, there are a few major rail lines, but mostly buses connect the towns. If you stay in a Konus town, these transportation options are covered by the Konus pass you get.

In the Bavarian Alps, train lines basically radiate out from Munich, but there are a lot of bus line connecting across the radiating train lines.

I don't have as much experience with Saxony, but I did stay outside Dresden one trip, and the local Verkhersverbund (VVO) pass for Dresden was cost effective.

When we lived in Germany and had our own car -and we had gas coupons to buy much cheaper gas- the advantage was with travel by car. We generally avoided cities and concentrated on the countryside. It was great to travel by car.

Now we fly in to Germany for 10-15 days. We find the train easier and cheaper. We tend to visit cities and small towns. We do not have to bother with parking, gas, navigating, traffic (including expressways that become parking lots), car rental agencies, etc.

If we wanted to visit the countryside again, we might try a car rental for part of the trip. Gary

I would suggest sticking to using public transport, which is what I do in Germany. The Deutschlandticket could be a good deal for you as regards to convenience in using regional trains. Here is where you can just hop on. No seating reservations are taken anyway. The cost is immaterial, relative to all other conveniences.

From the your itinerary listed, unless you intend on seeing villages in Saxony, going out in the back roads, out in the sticks, as I've done in Brandenburg seeing these villages, you don't really need to have a rental car.

For me it would depend on a couple factors. Mostly related to time/convenience.

I'd start with picking my preferred destinations based on my personal interest. I'd research and, normally, build a Google Map with places saved with green -want to see- flags. It's not just "the black forest area", it's which destinations, specifically, in the black forest area? The more research you do, the better your list of destinations will fit your interests.

Once I've picked those, I'd start mapping out an itinerary to allow me to see as many of those as possible. You will find you have to bypass some because they are just too inconvenient to include.

Once I have the itinerary, then comes the transportation question. First question, can I get to these using public transport? If the answer is yes, it begs the question, how conveniently can I reach these destinations by public transport? I've found the DB (German trains) website helpful in planning. It helps give you a realistic picture of how much time and money to budget for transportation.

I'm guessing you will probably want a car; I think they are better for rural itineraries. I can't really say, however, without going through the steps above.

Definitely a car. This is not Italy, there is nothing to be afraid of. :D

If you are up to it, a rental would give you the most flexibility from my perspective. I can't speak to rental prices. German fuel prices are about double of the US. If you have never driven in the EU and Germany, you should think about it. Parking can be challenging and with a cost. It could be stressful. You need to plan your pit stops too.

Another vote for a rental car for its flexibility, especially is you’re going to smaller out of the way places. While public transportation could get you where you want, it may not be the most time effective method.