Is there anything I should direct him to pick up? Not too familiar with your scene, and he's not all that knowledgeable about beer in general. He's flying into Denver and driving to Vail. We have access to normal, run-of-the-mill Oskar Blues, Great Divide, and a little Avery, but that's about it.
Dry Dock DIPA, Hefe, and Tripel should all be on shelves and are great. Ska Modus Hoperandi is a good pickup as well.
if he can make it to the springs trinity is awesome pricey but really good stuff especially the sours (brain of the turtle and old growth should both be available)
Everytime I go somewhere I try to find the smaller breweries who won't expand their distribution any time soon (for the most part), and who bottle/can. In the Denver area, Dry Dock, Crooked Stave, Funkwerks, Golden City, and Backcountry come to mind