4 season suitability in a TT capabile of being towed by a F150 with 4 passangers on board? Not going to happen. First of all, there is no TT that is 4 season in your part of the country. South GA maybe, but definitely notmnorth of the Mason Dixon line.
Second, a F150/1500 series with 3 to 4 passangers plus stuff is going to put a serious dentmin your towing capacity.
Probably one of your best 3+ season trailers is going to be a Nash or Arctic Fox, both from Northwood in LaGrande,OR. Not the cheapest nor the lightest, but built on their own frame and stout, with good insulation. All but their smallest models will overload 150/1500 series trucks with more than two aboard.