Ours is a 2007 W&P 34RL, 38' fifth wheel toy hauler. My roof is one sheet of aluminum and I walk on it quite often?
The only real downside to these is the fading of the exterior gel coat finish. It takes regular maintenance to keep them looking nice.
I haul everything from my Harley / dirt bikes / kayaks / mountain bikes.
My mountain bikes hang from the ramp door, inside the garage.
I did add a second A/C unit to mine and have done several other upgrades as my wife and I decide to.
Someday I plan to add solar to mine as well, but that is a few years away.
Check out this FB group for more info;
https://www.facebook.com/groups/297956927275903/