Re: Worried about Heat/Humidity For winter months
You can use either infrared lamps or ceramic heat emitters in your set-up. I still have some IR lamps on some balls in my bed room as I enjoy watching them cruise the enclosure when they know feeding day is close.
If you stick with the IR bulbs always keep a couple of spares on hand. I can't speak for others experiences but, personally I have found them to have a rather short life (Most of them at any rate I have the odd one that just keeps going and going).
The ceramic heat emitters might seem more expensive but when you factor in the life you should expect out of these they are actually cheaper over their life time.
The space heater is a definite option and insulating the enclosure to retain the heat you put into it is another.
Substrate can help with humidity. Coconut husk, Eco-Earth, Cypress mulch and Peat Moss retain a fair bit of moisture so less misting is required, as can covering part of the top (depending on the set-up you chose to use).
Re: Worried about Heat/Humidity For winter months
If you just have the one snake you'd be better off ditching the tank and getting a regular reptile enclosure. Initially it's a bit more expensive, but once you factor in costs like supplemental heat for the room and your daily battle with humidity (and there will be one, I've BTDT and have the pulled-out hair to prove it), life becomes so much better.