Lily Mountain is in the Arapaho and Roosevelt National Forests and Pawnee National Grassland which means it is not a part of Rocky Mountain National Park and, thus, dogs are allowed on the trail and parking is free, albeit it is only limited to 4-6 cars. The trailhead is 10 minutes from Estes Lake in Estes Park, Colorado and is located on the western side of CO-7. The trailhead does not have water, restrooms, or maps. Primary activities include hiking and hiking with dogs but motorized vehicles and horses are not allowed on the trail. Mountain bikes are allowed but it did not seem like it would be fun because there are many stretches with steps that would require dismounting. Notably, the Lily Lake trails can be found only a half mile down the road and provide a more family friendly hiking experience. The following Google map contains an estimated trail line that should only be used to get the idea that the trail runs north for a mile before heading south towards the summit.
Lily Mountain trail is a 1.9 mile hike to the summit with a change in elevation of 940 feet, from 8,800 feet to 9,740 feet. The first mile is an easy, rolling hike with elevation changes in both directions and views to the north and east.

The second mile is more difficult because it is steeper. Nordic walking poles are recommended to reduce stress on ankles, knees, and hips when hiking down trails like this one. For the most part, staying on the trail is easy but the last mile is marked with cairns. As depicted in the following picture, the final several hundred feet requires the use of your hands to pull yourself up and over numerous rock conglomerations.

The summit is an amazing place to have a picnic because there is an unobstructed view of the entire Estes Park valley with enough level ground with which to relax on.

The summit provides a 360 degree view that includes Longs Peak, Mount Meeker, Twin Sisters Mountain, Estes Cone, and Estes Valley.
Hi Robert, Big fan of your Blog. I have hiked 3 of the same trails in the last month. Your info helped me to choose the right one's for the amount of time alloted and difficulty levels. Do you have any more info on backcountry camping? ( locations and rules )Thank you,Jeff
Jeff, I am glad our blog was helpful, thank you. Regarding backcountry camping, three options come to mind: Rocky Mountain National Park (call the visitor center), Lory State Park (call the park office), and Mount Margaret. Regarding rules, Lory State Park and Mount Margaret have designated backcountry camp sites so that you can minimize impact to the local ecosystem. I am not sure if Rocky Mountain National Park has designated sites but they do require a backcountry permit which likely includes an orientation session that reviews the rules. My guess is that all three locations advocate Leave No Trace principles as their primary rules.
I just remembered that some, if not all, of the Rocky Mountain National Park backcountry camping is propane stove only (no fires).