You could do a lot worse than head for Berlin. Lots of guys nude sunbathing in the Tiergarten (near the Siegessäule column), heading into woodland nearby for action. Very cruisy near the Lion Bridge. Plenty of outdoor action in the woods at Grunewald, (station stop nearby) and the Volkspark Friedrichshain is not only beautiful, but plenty of action early evening near the hospital walls.
For me, nicest beach (with swimming) is at Wannsee. Get of the S-bahn train at Berlin-Nikolassee and walk towards the lake. End nearest Wassersportcenter (possibly signed FKK) is strictly naturist and largely guys. Loos and shwers nearby very cruisy, but folk are pretty considerate, too, of other users.
Most of this also listed in Berlin Time Out Guide as well; happy travelling when it all opens up agian!