I thought I'd post some info for all to see after considerable effort to find it. In the Chugach state park you must be 1/2 mile off the road to hunt with a firearm. In the Chugach national forest you must be 1 mile from any camp ground or trail head (not trail, but trail head). There is no specified distance off the road or a trail in order to discharge a firearm while hunting in the Chugach national forest.
st park info from their website
nat forest info from phone conversation with forest ranger