Options hmmmm My ponderings,
For ease of access (especially for those travelling far) and, as we are just after basic camping and a bar to meet in, the Fox and Hounds ...could be a good option
I was initially gonna suggest Princetown for the friday night meet as it offers more options ( i.e. a campsite and 3 bunkhouses, 2 pubs and 3 cafes) than the Fox n Hounds Also, the evenings drive across the moor for those not so familiar with could be more pleasant than a 5 minute drive off the A30.
But
as Chewie says, the campsite can be noisy/crowded and the 2 established bunkhouses (Plume and Foxtor cafe) aren't supposed to be that brilliant (the newish one at the Prince of Wales is supposed to be good , but I can't find a link) and places will need booking....
hassle!
I'd be a little wary of an initial mass car based wildcamp meet near a road - personally would rather that any wildcamping would be a self-contained backpacking type thing?
Happy to contribute route suggestions/info (and 'guide' if I am there)