Along the road leading to the partly-abandoned settlement of St. Elmo, past the Mt. Princeton Campground, there's a wide, gravel parking area with a sign pointing to a cascade viewing area. Unable to see any cascade from the road, we stopped to check it out, and sure enough, there was a marvelous view of a series of rocky cascades of impressive total length!
Farther down the road, there's also a trail to the Agnes Vaille waterfall on Cascade Creek.