Where to stay between Salzburg and Luxembourg

ob1

I am looking for a nice area to send a few days between Salzburg and Luxembourg. On the way here we visited the Rhine, the Black Forest, Lake Konstanz and Fusson we are at a bit of a loss where to stay on the way to Luxembourg and would welcome some suggestions
we have had enough of big city's would like a picturesque area with some nice towns to visit don't like to travel more than 200 miles a day.

Thanks OB1