That was my original plan as that's how I built my raised planter beds at my cabin in Tennessee so I didn't have to dig into that damn clay. With 4 rows plus the lid, it's not moving.
And I've only seen them sold in 8 foot sections. For 12 foot you could do 1x8s in 12 foot sections then just secure them to buried 2x4 or 4x4s I'm the corners and one every 3 feet.
Each row is screwed to the one below it by 4" decking screws, 1 at each corner and two in between. Alternatively you can use 2x4s in the corners to anchor it but two of us had trouble moving it at 2 rows high, it's not moving at 4 rows.
As far as the landscape timbers, if you leave them 8 feet long and do an 8x8 enclosure you shouldn't have to cut them. Just bury the first row at least halfway in the ground and then stack them like the old Lincoln Logs, alternating overlaps on the corners.
The main enclosure is 8 foot landscaping timbers, Lowes and Home Depot sell them for about $3 each. The top cap is 1x6 to provide a lip so they can't climb over. Height is about 1.5 feet. Cost just under $200 with the other materials for the lid (wood, mesh, hinges and latches.
I split the...
As Tom said you can have your larger raised enclosure on the new property, then maybe a perimeter fence around that. Or maybe just fence off a section of the yard just for tort use.
My plans once I start adding more enclosures is to limit access to that side of the yard with a gated wrought...
I was trying to think of how to do the same in my Redfoot enclosure I'm building. My issue was housing a thermostat outside but this looks like it would work.
Never used the Zilla stat, all I have are Herpstats.
I personally use the Herpstats for my Torts and my Ball python. More money but it's accurate and isn't a constant off/on. It will ramp the power up to reach the temp then bring it down to like 10% power to maintain.
http://www.spyderrobotics.com/home/products.html