I went through Ferretti Road this spring and passed by the upper end of the dirt road that goes down to the Lumsden Bridge area. I put that on my list of things to do next time I was in the area but it looks like that's in the burn area.
I don't want to start a debate about forest management practices but I've been in national forest areas where there is so much down wood and brush it's impossible to hike off trail. A local area that is pretty bad is parts of the Silver Fork valley between 50 and 88.
I never thought about arson but some big Southern California fires in recent years were intentionally set. They have a couple of suspects in the American fire, found a burned out pickup and picked up two guys hitchhiking out of the area but no charges yet.
I heard they had a suspect in the Angora fire at Tahoe, a guy camping in the Angora Lakes area, had a campfire get away from him. The authorities know his name but never brought charges, not enough good evidence I guess.