We have a Gray Wolf 22RR.
While it's not officially sold as 4 season, it meets the technical requirements. We've had it in the low 20's several times with no issues.
Never drained the fresh water system. I do try to drain the waste tanks before a really cold night but that's habit as much as anything else.
It surprised us how easy it is to heat. Down to about 30F and a 1500w space heater is enough that the furnace never kicks on. We've only had it down to about 20F so not sure where the furnace would meet it's limit.
4871 empty and 2800lb CCC.
