You have a lot of choices with a F-150, up to about 25 feet (200 sq ft living area). Larger than that, you get into lightweight construction methods, which can be problematic for four season living.
I know people who live for extended periods in molded fiberglass TTs as short as 13 feet (about 65-70 sq ft), a bit cramped for me, and others who struggle with the 400 sq ft maximum that defines for HUD the difference between a RV and permanent home. I know a few that have lived in the 40-50 sq ft in the back of a van, or the smaller space of a tuck camper.
I suggest you start looking at the living arrangements in TTs of various sizes to find what meets your living space needs. Once you find a size, try to find it built well enough for long term, year round living. That part will be harder, and the cost might have you rethinking economics of TT vs hotels, since you are probably going to be paying rent for the place you set up your TT.
