The Northern Lite have a big tray that slides out of the basement that would contain the water from wet gear and you can pull it out and dump it.
You could make such a thing for any camper with a basement storage compartment if it hasn’t already got one.
Luxury doesn’t require slides, which are great, when they aren’t leaking and if you don’t have to put them out just to get in or use the camper.
Class C motorhomes are generally lousy off-roaders. 4WD examples are rare, too.
I don’t see that working for your intentions. They have way too much overhang, lousy departure angle and clearance. And they don’t like being twisted.
If you’re getting a single-rear-wheel, it doesn’t matter if it’s a 3/4 ton or 1-ton. They’re really the same truck unless it’s a Dodge, don’t buy a late model 2500 Dodge for a camper, the coil spring rear suspension is built too narrow in the frame and it handles awful with a tall load.