Keystone is known as a family-friendly resort with plenty of groomed greenies and blues (and an enormous snow fort), but don't be fooled into thinking that the terrain here is tame – with 3087 skiable acres and a 3128ft vertical drop, it's unlikely you'll get bored, regardless of your ability. There are three main mountains: Dercum (frontside), the Outpost and the Outback; it's also the only Summit County resort to offer night skiing.
The A51 Terrain Park is decked out with an array of jumps, jibs, rails and a Superpipe, but where Keystone really stands out is the string of bowls above the lifts, which are only accessible as hike-to terrain or, more temptingly, via snowcat. Snowcats run up to Outback Ridge for $10 per ride (9am to 1pm), but for the full experience – including one of Colorado's longest snowcat-accessed runs, Two If By Sea (1500ft vertical ft) – you'll need to book the full-day snowcat tour, which includes lunch and powder-ski rentals.
If you buy a pass of three days or longer, you get access to Breck, A-Basin, Vail and Beaver Creek as well.