I hate to tell you this... because this is a favorite of ours.  We come here every year in the autumn.  We play on Kebler Pass, we have pizza at Stash in CB, and at night - the stars oh how the twinkle!  But you will pay a price for these autumn skies.  It is cold at Lake Irwin at night.  Bring a sweater and snuggle up!
The Camp Host is a delight.  So many sites that are good with peaks at the lake.  You are in the heart of the Rockies.  Wake up and pick a trail, or point towards a road.  It is bound to be beautiful!