I have been looking for 10 years and there is no place close. To plink, you are going to be driving a while.
There is a free, public state range between Hot Sulpher Springs and Kremmling. It is the closest thing that comes to a place to shoot tin cans that I can think of. It is over 2 hours outside of Denver (out I-70 to highway 40, then over Berthod Pass, through Winter Park, Granby, and Hot Sulpher Springs, and Byers Canyon. It is on the right.)
There are some indoor ranges in the Denver Metro area. Outdoor ranges began vanishing from the area in the 1980's and are gone except for the private ranges and clubs.d. The only outdoor ranges in the area have waiting lists from 2 to 8 YEARS.
Some of the gun shops maintain a list of shooting ranges that are open to the public--generally in the fall. There are some excellent ranges that are taking new members, but they are over an hour outside of Denver. There are also some indoor ranges that are actively soliciting new members.
But, I am unaware of any place close that you can plink. I go to the Ranch in West Texas. It is only a 12.5 hour drive, but I can plink all I want.