I agree with most of what is said.

I would not consider less than 24ft, for resale, ease in tie down and room for cabinets later. Get the tie downs from Mac's. If you have the room a 28 would be good so you could haul a golf cart later. I have a 24 because I don't think I could back a 28 in my back yard driveway.

Get a winch, very important if the car is not running. If you are not driving it in I would pass on the expense of the extra door.

Get the very best tire and wheel combo you can probably 16".

You might consider a generator compartment even if you do not plan to have a generator now.

Consider installation in ceiling and doors.

Enjoy! After pulling with an open trailer for years I was surprised at how much I enjoyed the enclosed. One thing is that you always bring some shade.