The Black Forest, Lake Constance, Heidelberg's castle and old town, and Stuttgart's car industry, with the Mercedes-Benz and Porsche museums. The state is also home to Europa-Park, Germany's largest theme park.
One day is enough for Heidelberg, and a weekend works for Freiburg and the High Black Forest. To add Lake Constance, the Swabian Jura and Stuttgart, plan on about a week.
Quite a lot. The Höllental Railway runs from Freiburg to Lake Titisee, and the Black Forest Railway goes from Offenburg via Triberg to Konstanz. For the Feldberg, take a regional train to Feldberg-Bärental and bus 7300 from there.
Europa-Park, the Wilhelma zoo and botanical garden in Stuttgart, the squirrels at the Triberg Waterfalls, and Mainau island, where kids 12 and under get in free. Kids 12 and under are also free at the Mercedes-Benz Museum.
Yes, but currently only to the 102-meter level, about 520 steps up narrow spiral stairs. The upper gallery at 143 meters is closed for safety reasons, and construction work partly blocks the view from the first platform.
April through October, when boats run regularly and Mainau is in bloom. Winter is quieter and cheaper, with lower admission on Mainau and the Christmas Garden during Advent.