A lot can fit on a small space. Complete galley with upright fridge/ freezer, convection oven, four burner stove. Queen bed. Split bathroom, shower opposite. TV s front and back, nice sound system. Etc.
So right Sid it can be made comfortable in a wide range of conditions.
Are you thinking of partially built into the ground? Desert style?
The structure I'm thinking about would allow the coach to be parked under cover, which would greatly expand its weather comfort range.
Cheers Richard