I am a salaried employee who lives and works in Denver full time. As of late one of the companies retail locations has been struggling so my partner and I have been taking turns driving our own vehicles to aspen where we stay in a company apartment that is 15 miles outside aspen. The company will reimburse us for the mileage on the trip up to aspen and returning from aspen. My question is while I'm driving to and from the location and the apartment do I still qualify for mileage reimbursement?

Actually, there is no law requiring mileage reimbursement in Colorado at all. So your employer is doing more than the law requires.