CO and UA have started up a new shuttle bus service between their gates. The need to walk has been eliminated as of today. You can board the free shuttle service at Gate 32 for CO and Gate 92 for UA.

The bus runs every 20 minutes. UA on the hour and CO at 10 minutes past.

No published schedule at this time. I assume you will need to show a current boarding pass for the other airline. All of this is behind security.