My favorite destination has to be Portugal. I can park my camper van off-grid and for free in many places there. Throughout central Portugal, there are many small river beaches (praia fluvial) where it is wonderful to spend time.
There are many nice places along the coast with a view of the beach, both on the west coast and in the Algarve.
I'm going with my 8-year-old son. And I'm also visiting friends with an off-grid spot where we'll help out and get a taste of what it's like to live like that.
We would also very much like to go to Sweden to experience the longest day. We prefer to be in nature, and in warm weather, naturally by a river or lake.