The last time I was in Germany was in December and it was cold! good thing your waiting until the spring.. The Black Forest is known for its cuckoo clocks, honey, Black Forest ham,Black Forest Cake, Pork Knuckle and Black Forest gateau. Also the setting for many fairy tales.
The cities of Freiburg and Baden-Baden are popular tourist destinations on the western edge of the Black Forest and for outdoors you may want to visit the Triberg Waterfalls which are the highest waterfalls in Germany.
I can recommend one hotel in near Lake Titisee:
http://www.relaischateaux.com/en/sea...taurant/adler/
Write back if you have any more questions.