I suggest you do NOT use Google maps to get here. It will take you on unnecessary gravel, rural roads.
From Portland, travel East to Hood River on Interstate 84 and get off at exit 64. Cross the bridge into Washington and make a left on Highway 14. Travel West on Hwy. 14 for approximately 1 mile and turn right on Alt. Hwy. 141. Alt. Hwy. 141 winds its way up the Gorge for approximately 5 miles ending at Hwy. 141. Make a left onto Hwy. 141 heading North to BZ Corner - approximately 12 miles. Turn right on Glenwood Road - BZ Glenwood Hwy. (Logs Restaurant) and continue 19 miles to the town of Glenwood. Once in town make a right and drive East about 1/2 mile toward Goldendale. Make a left (North) on Mt Adams Highway. Drive 1/2 mile to the driveway on the right (Flying L Lane).
Make sure you set your odometer!