Put her in a pillowcase with some folded paper towels (in case she urinates). Then put her in a box packed with crumbled up newspaper as a cushion (actually pillow stuffing from a craft store works a thousand times better and is really cheap, but newspaper will do). This will provide her with a nice stable way to travel without sliding around inside a cage. If the temps along the way are going to get below 70, you might want to look into ordering some heat packs over the internet or look for some type of hand warmer from a sporting good store.

The heat packs or hand warmer can be wrapped in newspaper and kept at the bottom of the box underneath the cushioning.

I ship snakes all the time and the main thing is that they are stable and not being tossed or sliding around inside whatever you transport them in.

-adam