The BolderBOULDER 10k, run each Memorial Day in Boulder, Colo., is a bucket-list race no matter where you live. I ran it this year, my first BB10k since 2007, and was happy I made the trip. You can usually find relatively cheap flights to Denver, and if you don’t have friends to stay with, there are plenty of Airbnb properties in surrounding communities like Lafayette or Louisville, where my family stayed. The race itself is…