There are two safes in the RPD--one in the West Office and the other in the Waiting Room. Both yield valuable resources well worth grabbing. We won't spoil what's inside each here (spoiler: they're all useful items), but we will reveal how to open them. The safe solutions are found in memos scattered around the building, which we've detailed the locations of for all of you completionists out there.
Terry, there are many storage unit places closer to the airport, but then of course you'd have to rent a car. DIA Self Storage, for example, is less than 10 miles away. You can google map Denver International Airport, then "search nearby" for "self storage units" if you think that's something you might want to do. http://www.coloradoselfstorage.com/
Wilderness Exchange is within walking distance of Union and they require you leave a bag with them when you go into the store, they may be willing to stash your bag for a few hours. No guarantee on that, but an option if you can't find anything else. They are only open 10am-6pm on Sundays, so you may have to wait around a bit or pick it up early depending on when you get there and will be leaving.
“Fans visiting Sports Authority Field at Mile High should keep in mind that not bringing bags to the stadium will ensure the quickest, easiest entrance and exit to stadium events,” General Manager Jay Roberts said in a statement. “However, we understand there are situations where our fans have to carry personal items or check bags. Based on fan feedback, we are implementing a new locker rental program which will minimize wait times to retrieve checked items.”
The storage lockers were a “pilot,” the kind of small test that city government frequently uses to test a new or controversial idea. The city offered up the lockers for individuals to use for months-long stretches. At the time, city officials warned that “misuse of the lockers, vandalism, or other unanticipated results,” could force them to cancel the project.