The only reasonable way too access Olo Mountain is via a private timber road maintained by Longview Fibre. If you choose to visit this area on a weekday, you may be sharing this road with logging trucks - use caution! Below is a photo of the posted rules for using this area. The sign does say it is closed on weekdays, but I've been biking these roads for over 20 years with no problems. Just be respectful, stay out of active logging areas, and yield to all trucks.
Follow the Mountain Loop Highway east from Granite Falls for 4.4 miles. Look for a gated gravel road on the left side of the highway, just before a large sign that says "Masonic Family Park"(N48 06.950 W121 54.586 Elev. 600'). If the gate is open, do not drive in - this gate may be locked closed at any time.
Note: This area has many logging roads going in all directions. It is assumed that you have a USGS or Green Trails map of the area, and know how to use it.
Follow Road 100 north for 0.5 miles until the road forks (immediately after crossing Canyon Creek). Take the right fork (Road 200), and follow it for 4.3 miles to a large four-way intersection at Olo Pass (N48 09.560 W121 53.290 Elev. 1987'). Turn right onto Road 220, and follow it for 3.3 miles to the optimum viewpoint (N48 09.323 W121 51.754 Elev. 3380'). The views here are really not too bad for a stubby little foothill, with commanding views of Whitehorse, Three Fingers, Pilchuck, and the Puget Sound.
For you strange peak-bagger types (oh, wait - that's me!) who just have to touch the actual summit, continue up the road another 0.3 miles to a point just S/SW of the summit. The road deteriorates quickly here. It is best to not continue down the road in an attempt to get closer to the summit (ask me how I know this). Simply head north into the woods, which are surprisingly easy to navigate thanks to commercial thinning of the trees. After 0.2 miles, you're there. Nothing to see, but at least now you have the satisfaction of standing on the 14th most prominent peak in Snohomish County!
Question: Does anyone out there know the origin of the name Olo? I figured out that it means "scent" in Spanish, but I have no idea if this is related in any way.