Fly to Denver. Set your travel dates and comparison shop for flights. If you are very flexible, Jet Blue, Southwest and Frontier offer discounted last minute airfare. If your dates are firm, make sure to book at least three weeks in advance for the best rates.
Drive to Denver. If it is within your time frame, calculate the gas cost of driving. The scenery throughout Colorado varies widely by time of year and the summer has long warm days to make for plenty of daylight driving time. There are many scenic and historic byways to travel along. See resources for a link to scenic byways. If considering rental cars, they almost always offer discounts for renting a week at a time.
Take the train to Denver. Taking the train can be a relaxing vacation itself. Colorado has very scenic train routes and Denver has a large and historic train station with Amtrak's California Zephyr coming through daily. Amtrak offers significant discounts for AAA and AARP members and kids ride for a discounted price.
Take the bus to Denver. Greyhound is one of the least expensive ways to travel to Denver. The fares are as low as approximately $80 as of August, 2010 to go anywhere in the country, one way. The travel time is lower than driving yourself, and you can see the sights without the fatigue of driving. The best greyhound fare is the most binding; you must pay the entire amount upfront and the ticket is not refundable. Knowing your dates ahead of time can save you up to 50 percent.
