Baby ball, gargantuan cage-- suggestions?

[Carr]

I'm taking in a rescue ball python pretty soon. A friend of mine, who works a job cleaning out and restoring apartments, found a young ball python abandoned in a tank. She literally cannot find anywhere else to house him so she's giving him to me. I have a big 45L x 18W x 12H plastic cage. It is my ONLY available housing unit for the ball python and is actually the smallest unit I have (all of my snakes are larger adults.) And this is obviously waaaaaaaaaaaaaay to big for a little baby that will definitely feel insecure and not safe. I have to save a bit of money before I'm able to purchase a smaller cage or tank.

-Because of my mothers and my sisters insecurities over snakes, a tub unit is not doable. My family has a huge insecurity that the skinny baby ball python will escape and eat them all alive. So a caging unit is necessary.
-It will be a few months until I'm able to save the extra money for any "cage" type unit, because I'm currently paying a million and one different things off and only have enough money for an emergency vet trip if needed.

The way that this cage is manufactured, I can't install a divider without it being a huge hassle.

So basically, my question is this: Any suggestions for making the way-too-large environment more secure for the baby ball, without making the cage impossible to clean? I want to make the environment as stress free as possible for the baby.

Extra note:
The smallest UTH I have available is kind of large too. Ultratherm, 11" x 23".
I don't want to roast the kid if he doesn't feel secure enough to travel from the hot side to the cool side.

[I-KandyReptiles]

You can easily secure a tub set up with binder clips. Bungee cords or setting books ontopz

[Badgemash]

Lots and lots of hides, until you can set up something better. Empty granola bar boxes, paper towel tubes, fake plants. Anything you have sitting around that can make him feel safe and that you can keep clean (or throw out when soiled) until you're able to upgrade. What kind of tank was he in at the apartment? Could he stay in that one? Also what kind of person abandons a live animal like that? I'm glad you're taking him in.

[Carr]

I could create a secure tub set up but my family does not accept that logic.

The tank he was in was in was small and cracked in several areas, starting to fall apart. Not even worth putting together.

I plan on cluttering as much stuff as I can to make him feel safe while I can. I've never had to deal with something like this before and god knows how tricky BPs get when they don't feel safe enough and get stressed.

[3skulls]

I don't buy into a tank being too big. If you can keep the temps and humidity right and have plenty of hides, I think it will be fine.