Fort Collins is a 10/10 for me. This is place I've visited almost every year since being a kid, and…read moreit continues to pull me towards it.
Not only is this town big on their breweries (there are seriously so many unique, tasty ones here! Tour them! Try them all!), they have a ton of places for outdoor adventures. Horsetooth Reservoir is RIGHT there, and throughout the entire town there are separate trails that cross with other trails. My personal favorite is the Spring Creek Trail. Perfect for bike riding, running, or walking. There are volleyball and tennis courts along the trail, along with picnic spots, grills, community centers. If I lived here, I'd be biking everywhere. You could easily never need a car here. There are also very close options for river rafting, and kayaking (Which we've done in previous visits).
Fort Collins has a perfect small-college-town vibe, and I would have LOVED to go to CSU. The downtown area is so walkable, and the food is amazing, the cafes are adorable, the art is fun. As soon as you set foot in FoCo, you can feel how much locals love their town. This place is an utter gem, and so close to my heart.