I wont speak of code, because I dont know your specifics. That said, I have a similiar situation in a seasonal shack in the north ontario woods. We ran our 10/3 wire about 250 feet inside cheap 1" plastic pipe temporarily about 25 years ago, and its still fine. Gives it an extra layer of protection from treefalls and animal chews. Definitely not code compliant, but safer and neater than many hillbilly hookups I see up there.