The Glennallen area itself has quite a bit of private Native Corporation land (AHTNA). You would have to be cognizant of the boundaries, they don't allow hunting. With your friend being a "local", I would guess that he knows the land ownership fairly well. Most guys use ATV's to access the area and it will be hard to get a place to yourself.
There are some good animals in the area. Both the moose and caribou have been increasing in numbers and quality. You stand a chance at a good bull caribou. Moose will be tougher to find a real "trophy".
I don't hunt that area but might be able to offer some more suggestions if you start making plans. Send me a p.m. sometime.