We have a 1989 17' Bigfoot and I would say that sleeping six would be pretty iffy. Bigfoot counts the front convertible dinette bed as a double, the gaucho bed as a double, and the drop down bunk as a single. Realistically, think of them all as singles (with the bunk bed being suitable only for a child). Both the gaucho and the convertible dinette bed are narrow, really more like the size of a twin bed. My husband and I split up, with one of us sleeping on one of the beds and one of us sleeping on the other. Not all couples are willing to do that. Some have made modifications to make one or both of the beds bigger. Some don't mind sleeping really cozy!
We do love all the roominess of our Bigfoot and have camped in temperatures down around freezing but I wouldn't want to camp in it in really cold weather. Newer Bigfoots are much more well insulated, but will also be more expensive. Will you be boondocking
or camping in campgrounds/RV parks with electrical
hook-ups? If you have electricity, a small electric space heater will usually be enough to keep things warm. If you're boondocking
you'll need a catalytic heater (they have their pros and cons) or you'll have to run your furnace. The fan on the furnace is a big electrical
draw and will run your battery
down pretty quickly if you have to use it a lot. Just some of the things to consider!
Also remember that many people who fulltime migrate with the seasons, spending the warmer months in northern parts and going south for the winter. One of the pleasures of fulltiming
is you can go wherever you want!