We did this back around 2014 or so, but outside of Facebook, just people from the forum. Had a decent turnout for a first go, I wanna say about a dozen boats. Had a few sponsors throw in drawing giveaways as well. The hard part was finding a spot everyone could get reservations at the same time. We did it at the Prineville OR Reservoir in late August. Campround has a handful of cabins for those non-campers. Used to have pretty predictable weather and awesome water. Unfortunately the private resort/campground/marina out at the point went under a few years ago so gas is now a half hour away and last time I checked the water level is so low that only jet skis could launch and it felt like a quarter mile hike from the day use lot to the water line.

Unfortunately we were also a bit scattered and unorganized for that event. Some showed up a few days early, others a day late. Some had never been there before and took off to explore the area. Other smaller groups planned some tie ups. I don't think we ever got everyone together at the same time, except for when we did the drawings...

I'd be open and willing to help plan if there is enough interest.