To be fair, there have been multiple news stories about people setting fires in western Oregon, including a guy who was arrested in Portland, released, and arrested for the same again within 12 hours. There are nut jobs out there. What is being refuted is that there is some sort of coordinated effort by Antifa to do this on some large scale.
As for looters, we asked the state trooper at the barricade on the road to my brother-in-law's house. In typical understated law enforcement fashion, he said both state and county were patrolling intensively within the closure, and they had "spoken with" a few people. So they are out there, also, but I would guess it's more local methhead types than some Antifa conspiracy.
QQ