With my fishing boat, I tow it tandem, but you ruled that out. When we take our Malibu, we are in a similar situation that you are referring to, with truck, 5er, Yukon XL and 23' boat.
We almost exclusively camp those trips in either State Parks or Federal areas. Very few are large enough for me to keep everything in the campsite.
When they aren't I usually leave my truck in the parking lot (often in the boat ramp parking lot). If there still isn't enough room in the campsite for the Rv, boat and Yukon, the Yukon goes to the parking lot as well. I don't like to unload the watersports equipment from the boat, which means it needs to stay as near the campsite as possible.
