I will be in a Bike/Boat trip from Amsterdam through Utrecht to Maastricht this summer. Are the RLD boats still an option? Any action in Maastricht?

Sorry to report that the boats in Utrecht never came back, and there are no plans to change.
Pitty. They were really nice. I got to spend an afternoon there once, with WIm and Dogs.
It was during the year that Maxx was there. She could rock that boat!
Don't know a thing about Maastrecht.
If I am that far south, I just go the rest of the way to the FKK's in Germany.
i have some recommendations around Cologne, if you are interested.

Weasel

Don't know anything in Maastricht but Saunaclub Sixsens isn't too far from there and there's a bus you can take from Maastricht that stops pretty close to the club. I've never been but a friend took a trip recently and enjoyed it.