All camps/permanent dwellings in the areas you cite are on private land. There are no more dwellings on ANF lands...except for a few small pockets of interior private land in the ANF the dwellings are primarily along the roads you mention. My place sits on the site of a former small farm on 666 a couple miles below Minister campground..
Austin Hill road is locally known as Bull Hill road. It does not directly connect to 666. Where is the place you're interested in? Austin Hill Rd. or 666?
I used to own a camp at the top of Bull Hill Road. Sold it about ten years ago to a family from Ohio that didn't hunt. Wonder if its the same place. There was public hunting land within walking distance of my door. Beautiful area. Great trout fishing.
I believe Austin Hill road runs From Sheffield out towards Hearts Content? Also known as 2002? The VFW and Sheffield rod and Gun club are out on Austin Hill. about a Mile or so out of town. Not quite sure where Bull Hill is, but there is lots of good hunting between Austin Hill and Cherry Grove area.
I am on 666 along the Tionesta between Barnes and Henrys Mill. The water treatment plant is at the end of Cottage Lane and the Vet's Club is directly behind that on Austin Hill Rd (Bull Hill Rd). The land across West Branch is ANF and can be reached by wading it or driving around and up Bull Hill Rd. You can get to the ridge behind the property by truck very easily. There used to be a swinging bridge at the Barnes Cemetery to cross West Branch but its been gone for a few years now. Lot of public hunting and fishing in the area. West Branch behind that piece of property will be loaded with trout in the spring.