Ken Wilcox’s excellent book on hiking in Whatcom County is called Hiking Whatcom County. The following is an excerpt (from the 5th edition of the book) for Hike #44, Lookout Mountain, with geo-tag annotations:
Park on the shoulder nearby (don’t block the gate, N48 43.154 W 122 21.330; elevation: 496 ft). Walk up the road and stay left on the more level grade at a fork (1.2 mi, N48 42.271 W122 20.678). The route steepens, passing a pretty waterfall in the canyon below. After a long, moderately steep slog up the road, the grade finally eases off before reaching a fork with a green box (3.1 mi, N48 40.808 W122 21.167); left goes to the south summit. Head right instead and follow this up to the saddle (3.6 mi, N48 40.779 W122 21.463) where it’s possible to wander left a few yards on lumpy ground to a great view of Lake Samish, the Chuckanuts, the San Juan Islands, and Olympic Mountains. Just ahead, there are good views to the east of Mount Baker and the Twin Sisters Range (N48 41.019 W122 21.484). Just below the top, the road forks again (4.3 mi); stay right (left is restricted). The grade circles around to a rocky summit perch at the foot of a tower (4.6 mi, N48 41.318 W122 21.655; elevation: 2688 ft).
On the trip where I placed the cache (March 6, 2008), the “fork with a green box” marked the beginning of nearly 1 mile of trudging through snow.
Cache is a fairly typical micro hiding in a bush on the summit rock. (The difficulty of this cache is the trip, not the destination.) There’s a token $1 for the FTFer (perhaps to help defray the cost of trail mix).
There may be a completely valid southern approach (from off of Old-99). If someone approaches from this way, please send pertinent coordinates.
Many thanks to PharmaDude for the ready-to-place container. Thanks, too, to brewermd and Toni R for wisely adjusting the cache placement.