I've never had a problem with Douglas County. I've carried in Highlands Ranch, Parker and Castle Rock. No problems whatsoever.
The Douglas County Sheriff is very pro citizen carry. He is trying to be the sheriff who issues the most CCW permits in the state of Colorado.
He recognizes that having legally armed citizens is a helpful deterrent to crime.
The only jurisdiction where you should not open carry.... ever.... is Denver City/County.
Lakewood is questionable at this time as well, but that is a specific issue. I don't believe that OC there, for the most part, is a problem.