If you want to walk parts of the Schluchtsteig you can use the bus (or train) to have you returned to your starting point. There even is a special Wanderbus (hiking bus) that goes from end of April to end of October, but unfortunateyl only on week-ends and holidays. As we were there during the week we had use "regular" busses, but that worked too. You can get flyers on the bus connections in each tourist information.
For hiking from Lenzkirch to Schattenmühle, we did park at that car park above the Lotenbachklamm as there are very few busses from the Schattenmühle. From the Lotenbachklamm car park, busses drive to Lenzkirch hourly.
For our hiking tour from Boll to Wutachmühle we used the car park in Boll, walked to the Wutachmühle and took the bus back to Boll. They only drive five times a day (one in the morning, four in the afternoon), so we had to wait for more than an hour. The bus had been really full, I wonder why they don't go more frequently!
More information on the bus connections:
If you stay in a hotel in the black forest you even will have free public transport, as you will get the KONUS guest card.
There is a train station in Löffingen that connects the town with Rottweil (via Donaueschingen) and Freiburg (via Neustadt). We did a day-trip to Freiburg from Löffingen, and the train trip was very nice. It's a great landscape with its gorges and rocks. The train goes through the Höllental (hell valley) and stops in a village called Himmelreich (kingdom of heaven) - isn't this an interesting train line?
Löffingen Station was destroyed in Second World War because the Nazis used it to shop material ...
What you can see on the photo is the "thing" people did out of it after the war. Not very nice, but ok for what its needed.
Today two train each hour stop weekdays and weekends, one to Neustadt (from there connection to Freiburg im Breisgau) and one either to Rottweil or Ulm.
So you can reach Berlin in six hours from Löffingen, Freiburg in one, Basel and Strassbourg in two.
There go also some busses from Löffingen station, but only to the small villages around it ;)
OBS! On evening Löffingen station is the meeting point of the (Russian) immigrant and the village youth - not always a very nice place to be. Even if I think that locals dramatize the whole situation ;)
Just take a look and see where Löffingen is located. We live in a borderless region so you won't see the Swiss and French border on my map.
Freiburg is 45 to 60 mins to the West, Lake of Constance 45 to 60 mins to South East. Mighty Rhine Water Fall at Schaffhausen (Switzerland) is about 30 mins to the South.
Löffingen can easily be reached by car on Bundesstrasse 31 (B 31 - route verte) as well as by train (two stops an hour). More on those means of transportation on the other tips pages.
If you come by plane I either recommend EuroAirport Basel/Mulhouse/Freiburg, Strassbourg (Ryan Air from London!), Zürich or Stuttgart.
This map is part of my unpublished thesis on Löffingen by the way. (Had to reduce pixels, if anyone can tell me how to improove the quality, please drop me a line!)