I have a 16+3 yeti, to be honest if I were looking to haul a wheeler in addition to weight of the finished house and the items you keep in it I would be looking into the tandem axle options. Wheelers now are around 800#. Not to mention you have 4 ppl in your family, you will want the size of house that requires a tandem axle. 20~24’long.
If you are thinking of finishing the inside yourself to save some money you should know that it actually takes a lot more time than you would expect. Finishing an actual house takes less time.
I am actually wishing I did not put a bathroom in my house now that I did. It is so easy to use my 1 man flip over and small heater with the 5gal bucket/bag option. Let the heater run for 5 min prior to going out and it is toasty warm. The only perk is in really stormy wether.