This is a very popular hiking route within Colorado's Brainard Lakes Recreation Area that loops around a clear glacial lake and a babbling creek. The shortest route begins from the Long Lake Trailhead, but if the small parking lot is full you can also start from Brainard Lake at Niwot Picnic Area, which adds about a half mile to the round trip.
The trail passes through colorful wildflowers that compose the edge between forest and water. Relatively flat and smooth, this path can be enjoyed by families and kids of all ages. Keep in mind, however, that weather in this high alpine environment can change unpredictably. Be prepared with a rain jacket and extra warm layer, because showers and hail may pop up quickly during the summer monsoon season. Also, wear good hiking shoes because the trail is likely to be be muddy, and leftover snow may lie in shady spots even into July.
Wildlife is common in this pristine environment. Eagles, deer, elk, and moose are just some of the native inhabitants that may be spotted. Be sure to give wide berth to any wild animals, especially moose.
There are a few extensions possible from Jean Lunning. By following the Pawnee Pass Trail on the lake's north shore you can continue on to Lake Isabelle and even further up to the Continental Divide. Additionally, an unsigned spur trail on the southeast side of Long Lake heads up Niwot Ridge to fantastic views from the rocky alpine tundra above tree line.