Someone on the Erotic Highway board uses his RV for his sugar dating activities. (Search for = RV and author  = sweetman.) Quite a bit of it, too!  
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You are in or near Boston?  It's still a little chilly to go on a camping trip in an isolated area.  Rent a fishing boat?
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With schools closed down, there is probably a lot of privacy under the bleachers.

And you can bring your own food and prepare it there instead of going out to a restaurant also.

There's one in Burlington, and another in Tewksbury, and I'm sure other places.