Yes! You can take the westbound Bustang from Union Station to Lyons. The service departs at 7am and 8am on Saturdays and Sundays only. The adult fare is $7.50. The A Train from Denver International Airport terminates at Union Station where you could make your transfer for those traveling from out of town, The schedule, ticketing and up to date info can be found using this link https://ridebustang.com/estes-park/