A is at N42 29.172 W073 10.963, 1600 feet from B, which is at N42 29.018 W073 10.676, 800 feet from the cache (C). The angle between AB and BC is 30 degrees. The cache is north of B.
How you get there is up to you. I crossed a few trails, but they were not going in my direction.
You can check your answers for this puzzle on Geochecker.com.
Congatulations to Tenebrus on FTF