If you want to ski down the mountainside, you'll need to get to the top of it first. Jump on Franzosenberg lift and enjoy the ride.
You're spoiled for sightseeing choice when spending time in Todtnau. Franzosenberg lift is a good place to start here, but there are loads of other worthwhile attractions to appreciate. Feldberg Ski Resort, Schauinsland, and Steinwasen Park are not far from the mountainside transportation system and will fill in your day nicely.