My late husband (gone nine years) and I had every kind of camper, from tents to popups to TT's to Class A. After he died, I sold the 2,000 SF house and motorhome, kept one car, went to a 1500 SF house, then 800 SF house, then the van. No plumbing, no electricity, used camping gear, loved it! Very easy, very simple. Circumstances required staying put so bought a 15' TT and lived in it for over a year. Now am living in a 31' fiver, but recently acquired a Class B and getting ready to head back out there! Yay!
I have been happy in all of the above. Changes happened because life happened. But each was chosen to fit the circumstances.
Funny thing is, as I'm loading the Class B and thinking about using it, it occurs to me that I don't need to take the Coleman stove, the jugs of water, the lanterns, etc. i kept thinking, "Where can I store all the water jugs?" Then forehead slapped, realizing that water carried in the fresh tank weighs the same as water stored in jugs. Duh! And I may not use the grey and black tanks because then I have to find a place to dump them. Mainly I got the B because I want to include an occasional grandchild. It has the forward facing sofa with seat belts.
As for how much space, I like small spaces. Feels like a cocoon and so much easier to keep clean and maintain. If there was a second person, it wouldn't work for me.