You can drive up to Georgetown on Saturday May 26th for the burro race and to visit this cool mountain town. Check out the Hotel de Paris up there, maybe take the short train ride if you're into that (get tickets online, will probably sell out). It's a bit cheesy and pricey, but some people dig trains.
https://www.georgetown-colorado.org/...eorgetown-burro-race In Boulder, the whole weekend has a festival going on and the Bolder Boulder 10k is on Memorial day. You can still register and it's a fun race, even to walk/run it. It will end in the stadium of CU and you'll see yourself on the big screen. Nice way to get a souvenir t-shirt. I have a food truck coming to our building so we can watch the race and eat. It's nice seeing the pro's run by.
If you're interested or want something to do indoors, the Celestial Seasonings tea company give free tours and that's interesting. 6 miles from Boulder.
Rent bikes from University Bikes. If schedules work out, I can ride with you if you need a guide. I don't know if Mt. Evans is open yet but I went riding up Trail Ridge Rd last week in RMNP. That tops out at 12,000, Mt Evans goes to 14,000. When I went, the last section was still closed to cars, so you may get to ride with only bikes and hikers on the road. I have a RMNP pass and can carry four bikes on my car if you want to do that.
Boulder has a lot of restaurants with happy hours. If you can do an early dinner, you can bar hop and try different appetizers or cheaper food and drinks.
The Casino's are an hour drive from Boulder and it's a nice drive for a day trip. You can combine it with a visit to Golden, possibly do the free tour at Coors.
I don't know what Breckenridge will offer but you could do a different hike or bike in Boulder every day.