Need help with daytrip choices from Rothenburg Ob der Tauber

Wurzburg for sure. Must go to the Residence. Heidelberg for the old town and castle. Dinkelsbuhl & Nordlingen for their quaintness. Just my opinion as they are three of my favorites.

"Dinkelsbuhl & Norlingen" (Nordlingen or "Nördlingen" in German)

These places are somewhat similar to each other and to Rothenburg. Nothing wrong with visiting them in addition to R'burg, just a bit repetitive.

Bamberg is pretty special.

You could likely afford to make a small detour in Iphofen en route to either Würzburg (also a keeper) or Bamberg.

Heidelberg is a bit far and IMO less interesting than the other options on your plate.

Not to confound your decision-making, but a visit to the Franconian Open Air Museum would open your eyes to local life over the last 500 or so years. It's in Bad Windsheim, closer to R'burg than anything else you mentioned, and it's really good. You could combine it with a half day in Rothenburg (which is about all Rothenburg requires.)

Würzburg is my favorite town in Germany. A walk upto the castle (Marienberg Festung) or chapel (Käppele) across the river is a regular part of our visits there. The open air "stations of the cross" are an interesting addition to pilgrimage Käppele. We also like the Mainfränkisches Museum in the castle. Würzburg is definitely a full day and more for us.

Bamberg's old core is very scenic and very worth a visit.

We have not visited Heidelberg in decades. Castle grounds are great. We are planning to go there next year.

Nördlingen is a quieter version of Rothenburg. We walked the wall and enjoyed it. Then we visited the Ries Crater Museum and I did not expect much. In fact the museum might have been the high point of the stop. I am not especially devoted to the subject of asteroids striking the earth but this was well done. We unknowingly stayed past closing time and they kept it open for us.

BTW, Rothenburg is perched on a hilltop over looking the Tauber River Valley. There are multiple scenic country walks down into the valley. Detwang and its Peter and Paul church are a nice visit. You might devote part of a day doing this.

Consider Eichstaett and the Altmuehl valley

When in Rothenburg try to visit nearby Creglingen and the Herrgottskirche for the Riemenschneider altar. Yes, there is a very fine altar by him in Rothenburg, but the Creglingen one is amongst the most important German art works.

Absolutly. There are at least many art historians who consider it the most important extant work of Riemenschneider. You can extend your trip to Creglingen into a very nice day trip by following the Tauber valley to Weikersheim and Bad Mergentheim, both nice historical town with impressive castles. Near Bad Mergentheim, in the parish church of Stuppach, there is a masterpiece of Matthias Grünewald (the artist of the well known Isenheimer altar), the so-called "Stuppacher Madonna".

I concur with Russ's suggestions, though Bamberg depends on how far you are willing to drive for a day trip. Don't forget your bathing suits (may not be required?), there are spas in Bad Windsheim and Bad Mergentheim for a rainy day. Bad Mergentheim also has Schloss Weikersheim close by. I found Schwabisch Hall to have a very pretty centre and riverside front. I hope Iphofen is as nice as Russ suggests, I will be based there for a while in September.

Thank you everyone for your great advice and suggestions!!......you have given us lots of options to consider. Much appreciated!!