If your going to be full time and buying new you need to make sure that what your buying is warrantied for full time use because if you read the fine print many 5th wheels are rated for recreational use only (Vacations of a week or two ), also there are so many options today that were not available a few years ago. You will need to consider what you want like auto leveling G or H rated tires, upgraded suspensions,LED lighting and holding tank sizes if your going to be without hookups at times and some of these options are not offered on the smaller 5th wheels. I think you need to be around 35-36 feet to start to be able to find the sort of room and options for full timers , we are at 35.8 with our current trailer and we have not found anywhere we could not get in to however some sites have been pretty tight , we also have four slides so that makes it a bit harder on small narrow sites. We spend about 3 1/2 months a year in out fifth wheel and this size does work for us , good luck with your adventure