One of my favorite places to visit in any season is Bear Lake Trail in Rocky Mountain National Park. There is a series of very picturesque lakes there that provides a target rich environment for hikers and photographers. In summer the trails are quite busy on the weekends with hikers that span the entire age range, from those very young children in harnesses on mom or dad's back, to those very advanced in age who continue to visit.
Moraine Park and Glacier Basin campgrounds are nearby, which provide an easy early morning base to get started. Getting to the trailhead well before sunrise provides an opportunity to hike to Dream Lake and get a nice sunrise view of Hallett Peak.
Bear Lake is an easy hike from the parking lot at the trailhead - only a couple of hundred feet at the most. [Note: the parking lot is tiny compared to the number of people who visit, so there is a shuttle bus that makes round trips between the trailhead and a nearby larger parking lot. The shuttle serves several of the local trailheads.] The trail is open year round, but of course conditions can be impassable sometimes.
There is a trail that goes all the way around Bear Lake, and there are fine views of Hallett and Long's Peak. Another branch of the trail leads to a longer hike to the three lakes, Nymph, Dream, and Emerald. The elevation at the Bear Lake trailhead is just under 9500, The elevation change/distance to the three lakes are (in order, from the trailhead): 230'/0.5 miles to Nymph Lake, 437'/1.1 miles to Dream Lake, and 615'/1.8 miles to Emerald Lake.
The first lake, Nymph, features a nice view of Hallett Peak, and the reflection of the peak in Nymph Lake can be very nice.
The trail continues to Dream Lake, which is a bit bigger, and affords a great view of Hallett Peak in the morning.
The above video was taken from a vantage point higher up on a hill, looking down on Dream Lake.
The final stop in this branch of the trail is Emerald Lake. It is not unusual to see elk on this leg of the hike. There are also a number of picturesque water features between Dream and Emerald lakes.