First time to SW Germany, itinerary help please

I can possibly help streamline this for you. Since you're basing yourself in Heidelberg, consider skipping Baden-Baden (overrated if you're not into gambling or bling boutiques), and instead check out some of the wine towns on the Bergstraße (basically, route 3). If you're driving in from Frankurt, you'll see the vineyards on the mountains to your left. The best towns for wine along this route are Bensheim, Heppenheim (go here!) and Weinheim.

For day 3- Stores in Germany are closed on Sundays, although restaurants and tourist sites remain open. I personally think Rothenburg, although quite attractive, is not nearly as unique as advertised. But it sort of lies along your route of travel (particularly if you drop Baden-Baden), so why not?

Day 5- Are you flying out of Munich or Frankfurt? If the former, consider spending your last night at the magnificent Therme Erding resort, located a 10 minute drive from the airport. If out of Frankfurt... Wiesbaden, maybe? I also like the early 20th century Jugenstil center of Darmstadt, although this is not to every traveler's taste.

Heidelberg is a cute little town. Be sure to see the brass monkey on one end of the bridge.

If you are interested in WWII history you might consider visiting Nuremberg - not far from Rothenburg.

In Munich there is quite a lot to choose from. The town center is the Marienplatz. Nice looking buildings though many were rebuilt after WWII. Good museums and churches to visit. The Residenz and Nymphenburg are palaces which can be toured and which belonged to the Bavarian Kings. The English Garden is just north of the Residenz. It's a great area to walk and also to watch people surfing on the river. If it's a nice day you could visit the viktualienmarkt, have lunch and a beer in the beer garden..