The Deutsche Touring (www.touring.de, www.romantic-road.com) Romantic Road Coach leaves from outside Füssen train station (stop 3) at 8am. It arrives in Füssen at 8.30pm.
If you want to do the castles in a single day from Munich, you’ll need to start very early. The first train leaves Munich at 4.48am (€28.40, change in Kaufbeuren), reaching Füssen at 6.49am. Otherwise, direct trains leave Munich once every two hours throughout the day.