Cut from another thread:
Last time we visited the Sauerland, we stayed at Sorpesee (the Dam 617 didn't manage to breach), the Hotel Seegarten - they chucked in an excellent room upgrade, just a shame we didn't have time to use the roof-top pool. Weekends see the area swarming with bikers & some interesting old classics get an airing too if the weather is right.
There are some lovely rides available from there - north takes you to the Mohnesee, via Arnsberg. OK, check out the Dam, but the east end of the see is more attractive TBH, if a tad busy when the sun's out. However it's more rewarding IMHO to head south down the west shore of the Sorpesee which takes you to Finnentrop, then Attendorn & the Biggetalsperre (the largest lake/see); carry on along the west shore & at the southern end of the see turn east onto the 55; Next you come to the Hohe Bracht, a highpoint with a viewing tower. Then carry on east to the 236 towards Winterberg, until you reach the Kahler Asten, another viewing tower. Then south to Bad Berleberg to pick up the Eder river which winds it's way NE to Battenberg, Frankenberg & finally onto the 3rd Dam at the Edersee. Then repair as you will to Sorpesee or wherever you choose to stay. Now that is a great ride as long as the weather plays ball.
Do watch the old SatNav around here though. The nature of the terrain means you need to plan routes thoroughly, not just stick in a destination (unless you enjoy riding around in circles).