The conference site can be conveniently reached by various means of transportation.
The most convenient airport is Stuttgart. No matter whether you are arriving there or at Frankfurt or another airport, it is easiest to take a train to Freudenstadt Hbf - about 1.5 hours from Stuttgart airport or about 2.5 hours from Frankfurt.
If arriving by train, target for Freudenstadt main station ("Freudenstadt Hbf"). Connections are via Karlsruhe or Böblingen.
Please note that there are two train stations in Freudenstadt - "Hauptbahnhof" (main station) and "Stadt". In order to get to the Waldhotel, Hauptbahnhof is the more convenient station. To the hotel, it is around 2 km from main station.
We agreed for a special rate with the Taxi company "Kleinen", which is 8 Euro for up to four persons or 10 Euro for a larger cab for up to 8 persons. There should be taxis waiting at "Hauptbahnhof" with a sign "Taxi Kleinen". If not, you can contact the company under +49 7441 2484.
It is probably best to plan your trip with some online help. Below is a snippet from Google maps for your orientation (click on the Google logo to open a larger version of the map).