Yup, it is! My weather here in Central California isn't as extreme as yours is in New York, but I have two Aldabran tortoises. Our winters are typically 50/30 (day/night), and they have to be kept warm in the winter time.
Sure! Decorate it with a natural substrate, add weeds and grass for them to graze on, and provide some large trees and Opuntia cactus (if they don't knock it down). Did I mention a good strong barrier? If you want some aldabra housing info, go to Greg (ALDABRAMAN). He's the equivalent of a living caresheet.
This is what works great for us. I use 250w heat bulbs to regulate the heat. We put our adults in at 55f and below and keep the inside temps between 60f and 75f.