Greenbroker, there are local bus services from Baden Airpark to both Baden-Baden and Karlsruhe, they aren't that frequent - about every hour I believe and they don't run particularly late. For Strasbourg (where I live) there are various options but one is
http://alsace-navette.com , we use this company professionally for various airport connections and they are ok. Taxis are also an option, about €27 to Baden-Baden railway station, about €90 to Strasbourg, don't know for Karlsruhe as I've never taken a taxi for that route. There is no railway station at Baden Airpark.