'All Season' is whatever the manufacturer wants it to be, and for the owner, it's highly dependent on altitude and latitude.
To decide if you can survive the cold, you'll have to define 'cold'. There is quite a difference between freezing cold and -30f cold.
Dry camping or wet camping? Dry camping can be done at any habitable temperature. I'd be fine dry camping in my B at -10f or so. Any colder and it gets hard to use the outhouse.
Wet camping below freezing is harder. The plumbing has to stay above freezing.
Coachmen claims the Coachmen CrossFit is well insulated. On most models the fresh tank and plumbing are all inside & the black and grey are outside. On something like that, I'd be fine camping below freezing with fresh tank and hot water heater filled. I'd use RV fluid in the black and grey to keep them from freezing.