Getting to Estes Park is fairly easy - there are no high mountain roads to travel, even in the winter, and we are only about an hour and a half from Denver (Colorado's capital city and home of the nearest major airport).
There is no public transportation to Estes Park. Your options (short of walking or biking) are to drive, to take a private shuttle bus from the airport, or to beg a friend to come pick you up (my preferred method).
If you need to rent a car, you can do so either in Denver or at the local company:
Estes Park Rent A Car 1110 Woodstock Dr. Estes Park, CO 80517 (970) 577-9715 Reservations are highly recommended. You might be able to show up without notice during the winter, and they might be able to find a car for you, but in the summer, fuhgeddaboutit.
There are two shuttle bus services from the airport.
Estes Park Shuttle and Mountain Tours P.O. Box 1908 Estes Park, CO 80517 (970) 586-5151 www.estesparkshuttle.com I haven't taken the shuttle in years. Last time I did, well... suffice it to say I had to borrow a friend's car and I almost missed my flight. But rumor has it that the business has since changed hands, and hopefully has improved!
The other "shuttle bus" is a party bus! If you want to travel in style, check out: Estes Park Limousines 2031 Mall Rd. Estes Park, CO 80517 (877) 502-5466 (Toll Free) www.estesparklimo.com
As far as the beg-a-friend option goes, well, yes, I'm your friend, but not THAT good a friend! You're on your own. : )