Downhill drives and back uphill with the train
A perfect day trip is the "tour de Murg"
Once you have reached Freudenstadt it's a nice downhill drive along a beautiful Black Forest stream. To get back home you can just catch one of the regular trains in one of the towns somewhere along the route- depending on how far you want to drive. And with your KONUS-Card which you get at your arrival the public transport is even free.