Planning out first terrestrial set up.

[REM955]

So here is the current state of things:
While I am moving out soon, I don't plan on actually getting the snake just yet. This area I speak of will just be cordoned off until I have a cage to put there. Really just planning now.

I am looking at getting a Woma Python. I am looking to buy something for the adult size, assuming 6ft as that was the maximum I could ever expect. Safe estimate with the rest showing 4-5ft.

The space I want to use is 28" deep and I am thinking 6ft out is the maximum. A number of guides hover around 4'L * 2'D * 2'H, but I would like to expand it out to 6ft in length.

The questions:
I doubt there is an issue with increasing the size, but is there anything I need to do other than add more hides?

What kind of substrate? I see a lot of Aspen being mentioned, but wanted to confirm.

I am not building my own. Simply not handy. Anyone have a preference in U.S. vendors in particular?

Thank you.