The Most Epic 5 Day Aspen Itinerary (Spring+Summer). If you are visiting during my favorite time of year (spring and summer) and are trying to figure out exactly what to do in Aspen but have little time to plan, I’ve got your back! Here is a 5-day Aspen itinerary based on an Aspen trip I planned during their Secret Season (May-June). aspen itinerary | aspen summer itinerary | colorado travel | best things to do in aspen |