The 500 is a nice drive. Stop at the Tittisee
and Triberg for the waterfalls. Furtwangen has a very nice clock museum if you are into clocks - this is where a lot of the clock / watch making / precision engineering in Germany has it's roots. You get snowed in for 4 months out of the year, you'll have some time to fiddle in the shed.
Try to get your hands on some black forest cherry cake with coffee while you are there.
G