Been here every year for the last 3 years, the first year was just a Black Forest Trip:
http://www.ukgser.com/forums/showthread.php?t=249110
Last year we dropped in on the way back from the Alps, this year on the way to the Alps and next year I am going with the lads for a "Stag Tour"
The B500 is THE famous road, the "best" bit runs for about 30 - 35 miles from just south of Baden Baden to about where it is level with Fraudenstadt, this is a fairly major road and popular with sportsbikes, it is tighter towards Baden and opens out where it is level with Ottenhofen (fast 100+mph sweepers) about 7-8 miles from the Ottenhofen (L87) turn (which also leeds to Seebach and Pension Williams) it comes to a junction, from here onwards it is not such a great road.
Where it meets the L28 you can bear right to Bad Peterstall and then take the L93 / L96 to Wolfach which is a pretty valley run to a lovelly little traditional Black Forest town, some great bends and lots of unspoilt countryside.
Lots of other great back roads in the redion and easy to put together looping days out taking in great roads and pretty towns / villages.
The Black Forest area is quite small so you can use a single central base and pretty much get around the whole region (about the size of Wales)
As ever I would recommend Pension Williams for location and value - as long as you don't want city living, there are a few places to eat and drink and free public transport if you want to take a day off the bike and go to Baden (You get free bus and train transport with a card the Hotel gives you)
have a great trip