Hey, I'm going to the Black Forest. Our trip starts April 20th. Wierd. We'll be cycling from Stuttgart to Donaueschingen, but then down to Titisee, then Waldshut, bad sackingen (where you can walk across a medieval bridge to Switzerland), then upto Freiburg, across to Triburg, Rottweil, Turbingen, and back to Stuttgart.

Or we may be doing a round trip encompassing Heidelburg, Karlsrhuer, Baden Baden, then down to Freiburg, and back to Stuttgart via some points in the route above.

Becnal is right, though, those Bikeline maps are second to none. I got the Neckar Radweg guide, and it's invaluable, as is the Bett und Bike guide, which shows you the accommodation available in the area.
We plan on travelling somewhere between 30 to 50 miles a day depending on the local attractions, and figure it will take around 7 to 10 days to see what we want to, so be warned, if you want to make the most of the Black Forest, you'll need more than a couple of days.

Best of luck my friend. Maybe if the timing's right our paths will cross somewhere.