You didn’t mention whether you’re looking for a hard side or a pop-up type, but since you mentioned for four people I’ll assume you mean a conventional hard side model.
Some brands that come to mind are Lance, Adventurer, Arctic fox and Wolf Creek (by Arctic fox)…Depending on your trucks capacity, a few can even be had with slide-outs…When comparing, also consider the capacity of the fresh water and gray and black holding tanks…
A good rule of thumb is to first pick out the camper you like, then choose a truck with sufficient capacity to carry the load (i.e. single rear wheel versus double rear wheel, etc)…
