2nd more info.
For example there's a lot of suggestions for the silverton area, but if your into mountain biking, silverton area is no good. The mountains are too rugged. Their website used to even say so. But for scenery on foot or in a jeep it's amazing.
Resort activities? Summit county or any of the other areas with ski resorts. (The resorts have figured out they can make money in the summer as well). They host different festivals and have kid zones.
The Arkansas valley with Leadville, Buena Vista, and Salida have a wide array of things to do. Mountain biking, hiking, 14ers, 4x4, fishing, rafting....