For serious hikers, the climb up Mount Whitney is worth the effort. Be prepared for a 22 mile round trip with a 6,000 feet ascent. There are a few stream crossings and nearly a hundred switchbacks on the way up. Plan to spend up to 18 hours on the trail, so start early (3:00a.m.) and use trekking poles. The trailhead is at NFS Whitney Portal Campground.
Overall, Mount Whitney Trail is the 2nd most popular hiking trail of all 88 hikes in California.