That's basically what I do with my corn. I keep my room in the lower to mid 80s, since that's comfortable for me. Besides a UTH on one side, my snake has no heat. She stays entirely on the cool side and is active in a proper amount (she comes out in the evening and wanders around a bit before hanging out at the front of the tank). I have absolutely no issues with her. She eats properly, has never gotten sick, etc.
On the topic of fire prevention. Everyone mentions equipment, but rarely what to plug into. Extension cords are obviously something to stay away from. However, if they must be used, use heavy duty cords. Stuff that's designed to take a big load. The same goes for strip bar plugins.