When to Go
Denali's main season runs mid-May through early September. About 90% of travelers come in these months, and with good reason: warmish weather, long days, and all the facilities are open. Shoulder seasons (early May and late September) can be incredibly beautiful in the park, with few people around; plus, you can often drive your own car a fair way down the park road, since the buses don't run. In winter the only way into the park is on skis or snowshoes or by dogsled. You'll have the place almost entirely to yourself—most of the businesses at the park entrance are closed—and if you're comfortable in deep snow and freezing weather, there is no better time to see Denali.
You can do a bus tour of the park in a single day. Allow for all day, and try to go at least as far as Eielson Visitor Center. If you can, go out to Wonder Lake. A few buses go a few miles farther to Kantishna, but the views from Wonder Lake are better; there's no reason to go those last miles unless you're staying at one of the inholding lodges.
If you have more than a single day, the best thing to do is camp in the park. The longer you stay deeper in the park, the better chance you'll have of seeing Denali, which, on average, is only visible one day out of three. Again, Wonder Lake is the spot of choice.
It's also easy to fill a day around the park entrance, taking rafting trips on the Nenana River or going on some of the short hikes near the visitor center.
No matter how much time you have, plan ahead. Bus and campsite reservations are available for the summer season beginning December 1. Reserve tickets for buses ahead of time; call the numbers provided here or log on to www.reservedenali.com. Although you can often just walk up and get on something, it may not be the experience you're after. Advance planning makes for the best trips.