If you are leaving right now for Rocky Mountain National Park, this is where I suggest you go for late season fall color.
I haven’t been to Rocky this fall so I can’t speak to this year’s color conditions, but I have found good color in Rocky October 10 and even later. Your mileage this year might vary. These locations recommendations go from north to south
If I were going right now I would start at Horseshoe Park. There are usually some aspen with color late in the season.
While you are at Horseshoe Park, and go all the way west to the picnic area at the end of Endovalley.
Next go to Moraine Park. Most years you can count on some late season fall color. Be sure to drive all the way to the west end of the Moraine Park road. Aspen usually hangs around a long time on the western half of the road all the way to the picnic tables near the end of the road.
Next take Bear Lake Road and stop at Hollowell Park. At the picnic area there is an aspen grove on the hill to the west that turns orange late in the season.
Close to the Hollowell Park parking lot there is a nice view any time of year of Longs Peak to the south.

Sprague Lake, Hallett Peak, and Flattop Mountain. Rocky Mountain National Park, Colorado. October 2, 2010.
Next go to Sprague Lake. There can be color late in the year at the beaver dams near the east end of the parking lot and on the west end of the lake.
As you continue on toward Bear Lake, stop at Fern Curve.
“Fern Curve” is the name I gave to one of my favorite spots. Before the road begins climbing significantly to get to Bear Lake, there is a curve to the left with a couple of parking spaces on the right side of the road. Back in the woods to the right there are big ferns (about 6 feet in diameter) that turn from green to gold in the fall. If the parking places are full, just up the hill from Fern Curve (heading toward Bear Lake) there is a much larger parking area at the Prospect Canyon scenic overlook. You can park there and walk the short distance back down the road to get to Fern Curve. Fern Curve is not on any park map so I marked the spot on a satellite map and added GPS coordinates.
This time of year in Rocky we are usually talking small groves and clusters of colors, not huge hillsides.