Couples size CT - planning it

So we are thinking a couples size CT for full time living. Here are what we are thinking, and appreciate comments about corrections.
1) Four wheels to worry less about blowouts. All our stuff is there and don't want to lose it all.
2) Brakes in the wheels
3) Big enough for a regular queen size bed, and a 7 & 1/2 foot couch.
4) Shower stall/ bathroom box/ storage closet (maybe) composting toilet is good.
5) ability to put a false wall and AC plug in unit in or remove
6) some nice windows for lighting, and good fantastic fan vents
so first thing is what size, and do I need four wheels? am data mining discussions about couples who have done this so far.
1) Four wheels to worry less about blowouts. All our stuff is there and don't want to lose it all.
2) Brakes in the wheels
3) Big enough for a regular queen size bed, and a 7 & 1/2 foot couch.
4) Shower stall/ bathroom box/ storage closet (maybe) composting toilet is good.
5) ability to put a false wall and AC plug in unit in or remove
6) some nice windows for lighting, and good fantastic fan vents
so first thing is what size, and do I need four wheels? am data mining discussions about couples who have done this so far.