I understand what you're wanting to create this naturalistic environment for your sugar glider. I had reptiles at one time also, and I loved the way natural environments looked, though was always cautions about what's safe for particular species. They're all so different and what's safe for one isn't safe for another.
From what we know of sugar gliders, I would take special care to research carefully the materials you are planning on using and make adjustments and substitutions as needed for their specific care requirements and hazards.
One place to start would be research safe woods for sugar gliders. As for the other materials, maybe see if you can research what is used in constructing a habitat for sugar gliders that are kept in a zoo perhaps.
The size of your planned habitat sounds very nice and generous, I'm just sure you want to make sure you know what's safe and what's harmful to these wonderful creatures.
Wish I could be more help, and please let us know what you come up with.