Hey Pedro,
I mainly hunt small game up near divide/florissant.
I've always had the most luck looking around small creeksthat have thick spruce trees along one side. The rabbits really like the reeds for cover that grow near the creek, and the squirrels are in almost every spruce or fir tree.
You can't really go wrong if you use a topo or google maps and find a few creeks, and go check em out. The rabbits tend to be more active at dusk and dawn, but you can still find em middle of the day. Squirrels seems to go at it almost all day.