You're going to get a lot of opinions so check out as many as you can and take a hard look at how they are built. Some brands worth looking at in no particular order are Northern Lite, Host, Bigfoot, Lance, Snow Bird, Snowy River, Arctic Fox and others I can't think of.
Pay attention to type of insulation, double glazed windows, and very important, tank capacities. You may want to look at alternate heating such as "Platinum Cat" Heater for long term boondocking. Normal furnaces will kill your batteries in no time in cold weather. Also make sure there is warm air circulated around your water and waste tanks. Check out the seals around any slides to make sure you can stand cold winds or pull your slides in. Large propane and battery capacities are important.
Good luck with your search. Keep us posted on your progress and visit back here as this website has a lot of helpful experienced people.
