It depends on what interests you, naturally.

You might try Bamberg just prior to Rothenburg. It's known for its brewery-restaurants and has a fabulous old town zone without the tourist kitsch of Rothenburg.

Nördlingen is a Romantic Road town south of (and not unlike) Rothenburg.

Southeast of Rothenburg, you might look into some less-visited places on/near the Altmühl River. Weissenburg, Pappenheim, Eichstätt, and Regensburg (on the Danube) are all interesting, attractive places.

We stayed two nights in Rothenburg and felt that was sufficient. From there we drove via Dinklesbuhl and Nordlingen to Fussen for two nights. It being that your sister-in-law hasn't been to the area, Fussen might be a good choice to see Neuschwanstein and Hohenschwangau before heading to Berchtesgaden.

I was looking at Nuremburg. Thinking of staying overnight there, but then thought, it's only about an hour away, what about Nuremburg as a possible day trip if we stayed in Rothenburg 3 nights?

Is it difficult to find parking near the Aldstadt?

fourfortravel we will probably go to Neuschwanstein from Oberammergau.

At the moment our "circle" looks like this

arrive Frankfurt (we have friends to stay with in Darmstadt) ~ stay 3 nights, first day recover from jet lag and local, 1 day Rhine cruise, 1 day Mosel and Burg Eltz

drive to Rothenburg for 2-3 nights

drive to Berchtesgaden for 2 nights

drive to Hallstatt for 2 nights

drive to Heiligenblut for 2 nights

drive to Oberammergau for 3 nights

drive to Heidelburg for 1 night

drive back to Darmstadt stay overnight and then fly back to U.S. in the morning

It's a lot more short stays than we usually do, but my sister-in-law is retired now, this will probably be her one and only trip to this area.

"I was looking at Nuremburg. Thinking of staying overnight there, but then thought, it's only about an hour away, what about Nuremburg as a possible day trip if we stayed in Rothenburg 3 nights?

Daytripping either way is possible.

Is it difficult to find parking near the Aldstadt?"

I've never driven into Nuremberg. But yeah, probably.

I stick with trains these days. A "Bayern Ticket" (Bavaria ticket) daypass allows you to leave your car parked. 30€/day for 3 people, pleasant 1.5-hr. ride between Rothenburg and Nuremberg. The Bayern ticket is good elsewhere within Bavaria if you have daytrips to make.

Russ, the Bayern ticket sounds PERFECT how do I get it?

You can get the Bayern ticket at any train station (they sell them from the ticket kiosks, as well as at the counters).

Nordlingen was a charming town. We also really enjoyed Nuremberg, particularly for the history.

Bayern tickt info:

http://www.munich-touristinfo.de/Bavaria-Ticket.htm

It doesn't sell out. Buy it at any station ticket machine, and use it on the regional trains. To find itineraries with eligible trains, you must specify 'only local transport' under 'means of transport' at the DB itinerary page:

http://reiseauskunft.bahn.de/bin/query.exe/en

Wrenwood- in case you didn't know it, Oberammergau is fairly small. 3 nights seems like an awfully long time to spend there. I would suggest driving on to Fussen for 2 nights to see Neuschwanstein and Hohenschwangau, doing O as a day trip, and then adding a day to Heidelburg.

Have a nice trip!

Agree with Tfb - I liked Oberammergau a lot; it's little and charming but take a day from there and enjoy another stop. Good suggestions above.

I think 3 nights in Oberammergau will work for us. We probably have 4+ hours of driving from Heiligenblut to Oberammergau, so I don't anticipate getting there until late afternoon. That leaves us 2 full days ~ 1 day for Neuschwanstein and/or Hohenschwangau and 1 day for Linderhof, Ettal Monastery and maybe a trip into Garmisch-Partenkirchen.

However, if I wanted to make Oberammergau only 2 nights, we could stop at Neuschwanstein the day we leave, then continue on to Meersburg for a 1 night so we could visit the Gardens at Mainau the next day before driving to Heidelburg.

I did take Hallstatt down to 1 night since all we will want to do is walk around the village, shop, and admire the views. Not interested in the Salt Mines, and I'm not sure we'll get my sister-in-law into the bone Chapel, although my husband and I will go again!