I looked at their info and unfortunately, it's only roughly geocoded, their entry for the library earlier in the thread points you at the building center and not the east side. Maybe not an issue for this specific box but many will end up difficult to find without more precise hassling.

As you can imagine, an address for Mesa County Fairgrounds will only get you so far. My experience doing this in WA is that many counties can have data that puts boxes 10, 30, or 1000+ meters away from their true location... So I'm trying to keep things pretty tight for now.