From Steve Schweitzer's A Fly Fishing Guide To Rocky Mountain National Park, flyfishingrmnp.com:
Tyndall Creek flows in and out of Dream Lake. Small caddis dries are the norm to use in the summer. During off-color or high water times, nymph a Steve's Baetis or Tabou Caddis on the edge of slower runs and behind boulders.
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Getting there: From the center of Estes Park, take Moraine Avenue, also known as Highway 36 West, for 3.5 miles to the Beaver Meadows Entrance Station. Proceed past the visitor center and turn left onto Bear Lake Road. Take this road until it ends at the parking area for the Bear Lake Trailhead. This is approximately 9.5 miles from the Beaver Meadows Entrance Station