Cascade Canyon Trail

This is a really scenic trail in the Grand Teton National Park. If you follow the trail all the way it will lead you to Lake Solitude. 

This hike about 12+ miles round trip, depending on if you get the ferry across Jenny Lake (less with ferry). The actual hike begins on the west side of Jenny lake, if you do take the Ferry it cuts off about 2 miles of hiking around the lake.  But overall the Hike is quite laid back and very doable for intermediate hikers and above. 

There are short sections with a moderate incline, but overall the trail is very mellow, and enjoyable.

If you're looking for a longer adventure, check out Backpack Paintbrush and Cascade Canyons for a ~20 mile out-and-back trip.