dedmiston..your really having an issue fitting 5 dirt bikes? I have a 12' garage and fit a canam outlander max, canam renegade, yami pw 50, full size weber grill and 2 large coolers along with gear. Another time I fit the outlander max and 2 full size sport quads along with the gas grill.
yes, I have to get creative and no I cant unload one thing without taking it all out but I do it. I really feel what the op is asking can be done, there are options out there for travel trailer toy haulers that wouldn't put him over the weights of his truck.
I do agree the limiting factor is the truck, I wouldn't ever tow a large 5th wheel with a 3/4 ton again.