Mike, you might carefully read the owners manual in regard to what promises Keystone RV is ACTUALLY making about operation in cold weather. I recall several complaints due to salesmen being a bit more ambitious than actually allowed.
I think all it really means is that it has a heated belly and some additional insulation. It doesn't certify the RV (guaranteed) to a specific temperature.
I'd contact Keystone (not the dealer) and get any certification in writing...
No way it'd survive for long in -15...
There is a Keystone owners forum where you might find people with direct experience.
