Being a Colorado resident myself (I love in Steamboat Springs, a couple of hours north of Breck) I can objectively and subjectively write that Colorado has done a pretty good job of managing the Coronavirus. That being written though, there has been a recent uptick in numbers, although not as severe as in Arizona or California. Information on a county wide level about what is open or closed seems to change on a daily basis. I would try and find a website where you can check specific County numbers (Summit County in your case), and maybe even check with the local chamber of commerce before you commit to anything. One word of caution; I 70 goes right through Summit County, and Breck is pretty close to that interstate. It gets a lot of tourism, so take that into account if you're worried about being close to big crowds.