After reading 43 CFR 3715 again, I can confirm it is contradictory. The thing of it is, is the question of due to the remote location, is the construction of a small cabin reasonably incident?
Under 43 CFR 3800, it states that any structure, mobile or otherwise, placed on public land for more than 30 days does requires a plan of operation.
Like I said, very contradictory.
Guess the BLM and I have a different definition of permanent.