You can level the cage with styrofoam sheets under the end that's lower. Use a carpentry level to be sure it's level.
If you don't have a level, then you can use a glass. Just measure halfway down with a ruler, and mark the glass on both sides. Then fill with water so it's to those two marks. set it on the cage, and lift the one side until the water touches both marks again.
Foam tape doesn't sound really sturdy.
Extra hides can be cheap plastic bowls(serving bowls are often $1 each) and you can cut a hole in one side or on "top" (the bottom of the bowl normally).
They won't look as nice, but the important thing is the snake's happiness and health.
I think you need to plan money wise about feeding your animals, and make sure to read the caresheets.