Have you looked at
ALiner.comI have a friend with one, and it really does set up in 90 seconds or less. My only complaint would be no real bathroom, and the short size.
I have a 30' Bounder and enjoy my 100 gallon fresh water tank. The fact that I only get 8 MPG is fine, I barely travel 5,000 miles a year, so fuel costs are not significant. I love being able to shower daily for 3 weeks before needing to move and get more fresh water. By that time, I am ready to go to a place with a laundry mat and refill with water.
To each their own, I guess. . . I love being able to stay near a lake for a week at a time, or spend days near a canyon overlook. I don't know that I would enjoy being in a small RV.
Good luck,
Have fun camping!
Fred.