Asan sits on Marine Corps Drive west of Hagatna, roughly ten minutes by car from the capital and twenty minutes from Tumon in normal traffic. Guam's public transport is too limited to rely on for these sites, so rent a car or take a taxi if you are not on a tour.
The beach unit is easy to find along the coast road. Asan Bay Overlook is inland on Route 6; the climb is short but puts the battle landscape into much better perspective.