Sounds like you are doing about all you can Lori. One other thing you could try would be to leave her overnight in a small ventilated deli cup or similar container with nothing but a f/t pinky, put her and it in there right before bedtime, and just leave the container in the snake cage in case she gets out, and to keep the cats away. put it in a decently warm spot, but not "on the heat" since she wont be able to escape the heat. Leave her overnight and see what happens. Just an idea.
Sometimes they are just plain stubborn.