Plywood works fine for a LDT but the 12k tractor will make short work of the plywood unless its 1" thick. Then where do you put the plywood or even haul it.
If you have the same place to park the trailer at the storage yard get the owner/mgr to gravel the 15 feet or gravel two tracks for the duals yourself for the 15 feet.
The problem with a HDT is off the pavement especially in grass and wet soil. The front end of a HDT sinks and sometimes even chains on the rears will not push or pull the steer axle through mud/soft dirt.