Quality /durability of Shasta Phoenix 5ers? 34RD?

There are very few if any trailers or 5th wheels that are 4 season. They may say so and the insulation factors might imply that but the windows and slides and leak associated with them will overpower any of the effects of the insulation. Check the insulation and seals on the slide's floors, walls and ceilings and you will find real weak spots for 4 season living. Trying to live in a RV under 35 degrees is risky at best and can be very expensive to heat.