If it were me....
I'd go with something along the lines of the Oz tent with its own awning. The problems with RTTs, and the same problem you'd have with the awning/room, is every time you want to move you have to take it all down. You can bypass all that by mounting it all to a trailer, assuming you want to tote a trailer around.
I've done both of those, and the first gets old real freakin fast. The 2nd wasn't bad for me but unless you have a dedicated camping trailer, you're still tasked with removing all that stuff when you need to use the trailer for more mundane stuff like carting plywood or picking up a load of tires for your truck, I mean expedition vehicle, and other chores. That was the case for me.
I'm considering the oz tent with awning as a free standing outdoor "space", some place to hang out, more than a sleeping area. I could drive my van right up to the awning, just like pulling up to a drive through, and pull away the same.
Anyway, another viewpoint.