No mention of your intended areas to be traveled, the things to consider are ground clearance, CG, balance and loads, turning along with weight. IMO, a 4 foot trailer isn't worth the headache of pulling, a raised platform off your hitch might carry that load, 6 ft is more useful and 8 ft is even better. At 8 ft you could haul a motorcycle or boat(s), lawn tractor, mom's couch to the dump, it would be much more useful to own. Again, IMO going bigger than 8 ft has diminishing returns, it can carry more but what would you need to haul at 10 or 12 foot or more (????) and then you get into specially designated uses.
You can put that RTT on top of your vehicle, you may not need a trailer to insure, pay taxes on, maintain store......but folks want one lol.
As mentioned, width is the concern, best no wider than the tow rig and the same wheel base as the tow vehicle to follow you.
Guess I'm suggesting that you give more consideration to your needs, locations to travel, camping loads vs. other uses and you may want a dedicated camping trailer like a Scamp or pop-up, good luck with your choices.