From the shore above the Forggensee you can see Neuschwanstein, white and improbable on its rock, and behind it the mountains of the Ammergau Alps fold into Tyrol. Few views in Germany are so famous, and few so likely to be crowded, so the advice is to come early. The castle was built by King Ludwig II from 1869, was unfinished when he died in 1886, and opened to the public within weeks. Hohenschwangau, the yellow castle below it, was where he grew up. Tickets for the interiors are sold for timed entry and fill up in summer, so this is a place to admire from the road if you did not plan ahead.
The Forggensee itself is a reservoir, made in the 1950s by damming the Lech, and it has an odd feature: in late autumn it is drained, and the lakebed becomes a grey plain, only to be refilled in spring. In summer it is the largest lake in the area, with a smooth turquoise surface, sailing boats, a passenger ferry and a few beaches where swimming is allowed. The water is clean and cold, and the shoreline, with Schwangau on one side and Füssen to the east, is busy with cyclists on the lake path.
Füssen, with nearly fourteen thousand people, has fuel stations, supermarkets and a handsome old town that climbs a hill to a castle of the Augsburg bishops, with a monastery, St. Mang's, on the river below. The town was a centre of lute and violin making from the Middle Ages, and there is a museum on the subject. It also sits on the line of the Via Claudia Augusta, the Roman road that crossed the Alps here from Italy to the Danube. A coffee and a slice of cake in the old town's narrow streets is a good way to rest the legs.
For riding, the approach from the north through the Allgäu foothills is lovely, with rolling meadows and views of the peaks ahead. The roads near Schwangau are heavily used by coaches, so ride patiently and watch for pedestrians crossing near the car parks. The best light on the castle comes in the morning, and on a clear day in autumn, with the first snow on the peaks, the picture is fine.