Travel plans too ambitious?
 

So mu husband and I have about 10 days to "fahrt" around Germany with a car after visiting relatives near Dusseldorf.

The easiest & nicest thing to do is to go down the rhein, see the Dom in Koln, Burg Eltz etc., was considering going over to Trier, then back east to Stuttgart (I'd like to cut Stuttgart but my husband is trying to arrange a porsche plant tour) and then over to Rothenburg o.d.Tauber, Wurzburg and then high-tail it back north-west and all the way to Amsterdam for the flight home.

Looking at a map this seems crazy for 10 days (esp. the last bit) - do-able but not enjoyable with little time to explore small towns etc. I'm thinking we need to narrow our focus to the Rhein and Mosel and that's it.

Any advice?

I don't think your distances are that great and it seems very doable. Small towns sound nice but after a while one small town looks like another in my opinion and you'll see many of them anyway - ten days on that route seems leisurely to me.

Certainly take your time wandering down the Mosel...Trier would probably be my last stop prior to heading back north. Should you choose to leave Germany, Luxembourg & Maastricht would be in the general direction you need to go.

75--What time of the year are you going?

I'm going for the last two weeks of May.
Also we're hoping to just find Zimmer Frei or Pensions along the way. This should be ok - or should we plan a more firm itenary and pre-book rooms. We're trying to do it on the cheap.
(we'll be gone the week before World Cup)

Don't drop your car off in Amsterdam (or anywhere in the BENELUX), the drop-off charge is quite steep. Leave it in Wuerzburg and take the train to AMS.