Mark, if I were in your shoes, I'd probably attempt a season with what you have. Biggest reason, you just might buy something that is consider better insulated, and find yourself in the same boat. Just my 2 cents. With precaution, I think you'll be fine. Keeping inside warm is easy, it's the all the other stuff that tends to be a problem every now and then.
John and Rebecca Dickson
Emma-7 / Little John-5 / Iva-1
Full Timing Again, Rev B
2013 Ford F-350 Lariat CC LB PSD
2015 SOB TT - With OC's Awning Poles (#8)
At least in Heaven, RVs will be perfect, and I won't have to keep fixing them.