(Trailhead is shuttle bus accessible.) The easiest peak in the park is Flattop Mountain, a round trip up from the Bear Lake Trailhead. Although the route up is spectacular, the summit is less so though making the half-mile walk to Hallett Peak more than worth it. However, even though it is the easiest of the main summits in the park, even Flattop must be respected. People have died on this hike, mostly because they summitted too late and the weather closed in.
(Trailhead is shuttle bus accessible.) A beautiful morning hike, this Lake is situated on top of Bierstadt Moraine giving brilliant views of Longs and the Front Range. As three routes converge on this lake, all of which lead to Shuttle Bus serviced trailheads, this hike can be done many different ways or even tacked onto a bigger venture. Arguably the best route is from the Bear Lake Trailhead to the shuttle parking lot as this stroll is mostly downhill. Walk down, take the bus back up.
This short hike leads to the top of a foothill near the edge of the park that gives a great view of the front range. A 3-mile hike, the trail is really close to the edge of the park which spoils some of the wilderness feeling you can get far inside the park, however the view from the top is more than worth it. The Lily Mountain Trailhead can be found a little ways south of Estes Park along Route 7.