First time owner needs advice on materials

[Gothappysack]

I am a building an indoor environment for my new Russian tortoise female. She is about 5.5 inches, and I need something better ASAP. I have a space 6'x6' in my apartment that I plan to use. I will try to get more space, just because.

With an offset shape or an "L" might I be able to make it more interesting for her?

Can I use plywood and MDF for the structure with plastic liners for the substrate?