I know it's a little bit of a drive, but once you get out around Limon they are begging for people to shoot them.
Coyotes too.
The closer you get to Kansas, the more willing people are to let you hunt their property.
A bonus, once you get to know these people, most will also let you hunt their "prairie maggots" as they call them.(Antelope)

If you get a yes from somebody don't forget to ask if they know of anybody else that has a problem that they would like help with and they will usually tell you the next person to contact....so the door knocking ends.

I usually go out to Seibert and Flagler, just south of I-70.

Stopping at the little towns and going to local businesses like the Co-op usually works as well, since everybody knows everybody and knows where the problem areas are.

Some of the "problem" areas are miles wide and miles long.