Every time I travel to a city with decent public transportation, especially one with a reputation for horrible road traffic, I do my best to take full advantage of public transit. Why drive when you can relax and enjoy a safe ride on the train? The University of Colorado A Line from DIA to Union Station in LoDo is just perfect for a traveler like me.
My best tip is to install the RTD Tickets app on your phone long before your trip. From there, you can purchase your $9 pass ($4.50 for students & seniors, free for active military & kids under 6) up to 45 days in advance and you have no reason to wait in a kiosk line with everyone else who did not plan ahead.
A new train into downtown Denver takes off about every 10-20 minutes and there are 6 stops between the airport and the end of the line at historic Union Station (across from Coors Field and near tons of other food/drink/entertainment options). See the light blue line on the transit map image I've loaded to this biz page. The trip takes around 40-45 minutes, during which time you can be occupied with other things besides navigating the packed roads in an unfamiliar city.
When you're on the train, there are racks for your bags near the doors, as well as overhead; you can't keep bags in the walkway. An armed agent will come by to scan your ticket once, maybe twice, during your trip. Within the smartphone app, just go to your ticket wallet and activate the ticket that you purchased earlier, show it to the agent, and you are good to go.
From the airport:
Follow the signs to baggage claim and transit. See the DIA map I've added to this listing to find your path from your gate to the Transit Station (Stop 34475). You'll descend down a long escalator through some interesting abstract art to the A Line departure area. Check the westbound schedule and which track you need to take here:
http://www3.rtd-denver.com/schedules/getSchedule.action?runboardId=2514&routeId=A&routeType=32&&direction=W-Bound&serviceType=4#direction
https://www.rtd-denver.com/app/nextride/stop/34475
To the airport:
On a weekday morning, another train takes off from Union Station (Stop 34667) about every 5-15 minutes. Check the eastbound schedule and which track you need to take here:
http://www3.rtd-denver.com/schedules/getSchedule.action?routeType=32&routeId=A&serviceType=4
https://www.rtd-denver.com/app/nextride/stop/34667 read more