Help with May/June 2016 Europe Itinerary (3 weeks)

"Our plan is to fly to Frankfurt and rent a car to drive to Rothenburg ob der Tauber (2 nights-hotel), then drive the Romantic Road to Bad Tolz..."

I advise against driving immediately after a transatlantic flight (jet-lag, drowsiness, unfamiliar surroundings, German Drivers. ) It would be better to take the train to Würzburg, IMO a Romantic Road town which shouldn't be skipped. There are two train stations right at FRA airport and you can get there in 1.5 hours by direct train.

Würzburg
Residenz in Würzburg (UNESCO World Heritage)
Würzburg sightseeing

Unfortunately for those who are lured by the Romantic Road marketing scheme, there are some really good places near Würzburg that the Romantic Road just doesn't include.

Bamberg is a UNESCO World Heritage town, an outstanding place that isn't on the Romantic Road and a great day trip from Würzburg (easy by direct train.)
Iphofen is an adorable wine/artists town with old town walls and towers - also easy to reach by direct train.
(Nuremberg, Bad Windsheim, Marktbreit and Ochsenfurt are further day trip options.)

I'd spend 3 nights in W'burg and do whatever day trips suit you. You can pick up a car in Würzburg when you leave for Rothenburg. Rothenburg, as Rick Steves admits, "...is well on its way to becoming a medieval theme park" and stuffed with international tourists. I would just do a stop there for a while before continuing south to Bad Tölz (6 nights there if you want to keep on schedule.)

Alternatively, you could stay 7 nights in Bad Tölz and then "save a day" at the end of your trip to "pay" for staying 3 nights in Würzburg; stay your last night in Bacharach and take the train to FRA on the day you fly out. Trains leave quite early in the morning from Bacharach; there's direct train leaving Bacharach at 5:37 on most days - takes less than one hour to drop you at FRA.

As for the car, I can see why you'd want one for Bad Tölz, but I wouldn't want one for the rest of the trip. The Rhine towns are well served by trains on both sides of the river.

Russ,
Thanks for your great ideas. I does make more sense to take the train upon arrival. Wuerzburg looks less touristy (which we like) and we will plan on stopping there for 3 nights.
Many thanks for your thorough and helpful post!
Becky

I assume that you have already booked your flights. But if you have not, then I would make a multi-city flight booking, moving Bacharach to the start of the trip, moving the night budgeted for Frankfurt to Vienna, and flying home from Prague or Budapest. If that meant that you weren't jet-lagged upon arrival in Rothenburg, you could also cut a night from Rothenburg to give to a bigger city.

Laura,
Many thanks for your response. We have booked our flights. We used points (I travel for work) and unfortunately, I could only find great flights to and from Frankfurt.

I'm sure staying in Bad Tolz will be nice, but you're going to be about 50 miles south of Munich. Munich is too great of a city to do day trips into as it's really a 4 day destination to visit the "right way." I would need a designated driver on any trip to Munich.
Salzburg is 2 hrs. east of Munich and it's worthy of a 2 day stay.
Vienna is a 4 day city as it's the Music City of Europe with fabulous palaces and museums.
I've stayed in Bacharach a number of times, and it's more of a place to spend one night--and not a destination. You can walk the city from one end to the other in 15 minutes. I wouldn't go out of my way to visit there, and would take those 3 nights and apply them to the above mentioned cities.
While I'm reallocating your time, choose either Budapest or Prague. They're cities that are very much alike. After visiting both on the same trip 20 mos. ago, I would pick Budapest as my preferred city.

We like to travel in a straight line between cities via trains that compliment each other. Like Budapest-Bratislava-Vienna-Salzburg-Munich. Or, Budapest-Vienna-Prague-Dresden-Berlin. None of those train rides are very long, and each city is unique--and absolutely great.

I'll agree that Bacharach is not a destination. But a 3-night stay there or in a neighbor town puts the rest of the Middle Rhine Valley and more at your feet - and 2-2.5 days will go very quickly:

http://whc.unesco.org/en/list/1066
http://www.welterbe-mittelrheintal.de/index.php?id=288&L=3
http://www.welterbe-mittelrheintal.de/index.php?id=274&L=3
https://www.k-d.com/en/home/
http://flyhahn.com/regions/holiday-regions-germany-frankfurt-hahn.htm

David,
Thanks for the suggestion of spending more time in Munich. We decided to change our plans to stay there 2 nights.
Thanks again!

Russ,

I am just getting a chance to look at all of the links you provided. I am finding them really helpful.

Thanks so much!

Becky