Aspen Mountain is located 222 miles (by road) from the Denver airport (DEN), 128 miles from Grand Junction Airport or just 4 miles from the Aspen Airport (ASE).
Your choice will depend on whether Aspen is one of many destinations or your only destination.
There are four Aspen resorts in total (Aspen Mountain, Aspen Highlands, Snowmass and Buttermilk) and all are reasonably close to each other and to the town of Aspen.
Each resort and the town of Aspen are served by a convenient city bus.
In fact the bus is so convenient that a car may be a liability, as parking at Aspen Mountain is limited and expensive. The resort is literally at the edge of town and parking in the town of Aspen is difficult.
If you choose your accommodations appropriately, you may be able to walk to the resort and hopefully be able to walk to all of your evening destinations in town.
The Aspen-Pitkin County Airport is served by United Airlines from Denver Airport.
Denver International Airport is served by most major American carriers from most major American cities.
Airport shuttles can take you from either airport to your destination in Aspen.
Access to Aspen by automobile is by Highway 82 connecting to the main Colorado Interstate Hwy 70.
Note that access from the South through Independence Pass on Hwy 82 is typically closed in winter.