Sweet idea! I too am a bit concerned about the light bulb heat. The main reason being that light bulbs are so notorious for sucking out the much needed humidity, not to mention they can get very hot (cage and all), and waste so much energy.

If you were thinking about alternatives to the light bulb, I would check out some flexwattt, and also radient heat panels. You'll find they are simple to control with a good thermostat, and also won't burn your snake. (If used properly anyways)

I would think about it, I'm sure you'll find the humidity a struggle to keep above 50%.

With a good thermostat like a Ranco, Helix, Johnson or others, and a nice bit of flexwatt or radiant heat panel.... you'll have great success!