have you ever thought of a small travel trailer.
There are some nice 19 footers, that have all the luxuries of home including a queen size bed, showewr lavatory, toilet, dinette, microwave, refrig with freezer, kitchen sink, range and oven and wall cabinets as well as various wardrobes for storage
We used to have one, but the one we have now is a 25 footer.
I pull it with a full size pick-up, with a fiberglass top and haul three boats on the top. All our paddling gear, snorkling gear, mountain bikes, and back/yak packing gear goes in the bed.
Leave the trailer at the campground and take off with your boat(s) of choice.
The total cost should come out less than a RoadTek or a high end camper van.
With that said, we have a friend with one of those high vans, and he some how or other gets one boat on the top.