A lot of the single axle trailers have very little cargo carrying capacity so be aware of that. With four people it would be easy to overload, I looked at one last year that only had a couple hundred pounds after the battery, propane, and water were filled.
That brings up another point, tank size. Most of the smaller trailers have small tanks which could be a problem if you plan to boondock for more than a couple days, especially for four people.
Having a plan for having four people in the trailer for an extended time if the weather is bad is a good idea. Mine has a decent size dinette dinette we can sit at and play games though the cushions could be a little more comfortable. Windows help to make a small trailer feel bigger.
