Think about it. In winter, the general traveler can enjoy some version of downhill riding (skiing, snowboarding, tubing), cross-country skiing, and snowshoeing. There are more extreme opportunities, such as these, but the average person is probably going to stick to the slopes or a walk in the woods. Then you look at what the summer brings in terms of camping, hiking, mountain biking, climbing, and rafting. You can tackle more experiences in a single day, and the nice weather and extended days further expand your options.
There are lots of independent adventure outfitters in small, non-ski mountain towns across the west (think Leadville, Grand Lake, etc.), and locals certainly have their favorite go-to spots, which they are able to access due to the fact that they live nearby, have access to a car, have knowledge of the trails, etc. You can definitely tap into this scene if you do your research.
If you're willing to spend a little more for full service, staying at a "ski resort" might be a good fit. During the summer, the ski lifts can be used to access elevated terrain and trails, and have racks to transport mountain bikes to the top of the hill. Ski resorts usually have concierges that can help you plan other outings, such as rafting or climbing. For families and general travelers who aren't experts on adventure travel, the extra hand holding can go a long way.
Plus, although developed, ski areas are still incredibly beautiful, so you don't have to worry about sacrificing anything in that department. If you're looking for a mountain getaway this summer but don't have time to plan it out to death, keep the usual winter suspects of Vail, Aspen, Park City, Taos, and Tahoe in mind.
[Photo: Will McGough]