RE: Colorado what week?
The first week of September is not bad. The Muzzloader hunters don't start until the 2nd week, and most of the archery deer/elk hunter are gone after Labor day. Good Pre-rut action.
I have only hunted high country back pack, so I don't have a good feel for the pressure or action at lower elevations.
I have never hunted after the Muzzloaders have left, later in the month, but I assume the rut is in full swing and the elk will be bunched in isolated pockets.
Good Luck!