Drive I-5 to just north of Mount Vernon, then east on SR 20 (North Cascades Highway) to Marblemount. At Marblemount, turn right onto Cascade River Road. Drive ~20 miles to a large parking area on the right (2,100 ft).
From the parking area backtrack downstream about 90 feet on the road (look for possible flagging), looking for a clump of three trees crossing the river, or one large log. Cross the river and walk about 100 feet perpendicular to the river until you find a climbers' trail.
Go right, or east, upstream on trail. Proceed up and slightly right in open timber following climbers' trail. Stay to right (east) of large windfall and traverse up so that Eldorado Creek is within earshot. After about 1500 feet of elevation gain, reach talus slopes. Ascend talus (cairns and flags; do not cross Eldorado Creek) with large cliffs on the left. Ascend in he center of the talus field and into cliffs with a climbers' trail to upper boulder field.
Ascend up and right (east), picking up segments of fair-to-good way trails into a large basin at about 5,500-5,800 ft. Move up onto ridge on left to small, but level, camp spots (6,100 ft). Look for way to drop down into Roush Creek Basin—the best spot found north along ridge. Campsites in Roush Creek Basin between 6,100 and 6,400 ft.
From Roush Creek Basin, proceed up snowfields and Eldorado Glacier just left (west) of rocky ridge. Follow this to broad flat area of Inspiration Glacier at about 7,500 ft (there are good camps near the rocks). Traverse Inspiration Glacier around to north and follow broad snow covered ridge to top (8,868 ft). The summit ridge is a spectacular knife-edge of snow.
TRIP PROFILE
KEEP CLIMBING MOUNTAINS & DON'T SLIP