You might need to narrow down what *type* of breweries you want to visit… There are 8-10 just in Boulder proper. Add FoCo and the Denver sprawl and it's 100-150 depending on how far you're willing to drive.
In Boulder, Mountain Sun/Southern Sun is a good brewpub experience, as is Boulder Brewing (the first craft brewery in the state). Avery and Twisted Pine have good beer and smaller menus; I haven't eaten at either. Then there are the breweries/taprooms - I haven't been to Upslope, but some of their canned beers have been quite good, and I've heard good things about Fate.
If you go up to Fort Collins (which is very out of the way for a drive from DIA to Boulder), check out Funkwerks (all-saison brewery, and IIRC they have some charcuterie/cheese/tapas-type food at the taproom). Equinox has some great beers, and Cooper Smith's brewpub has been around forever.
I don't even pretend to keep track of the openings/closings in the Denver area. Crooked Stave is well worth a stop if that's your cup of tea.