This is the place to go for solitude, wilderness, and abundant wildlife. The Denali Visitor Center, open in summer, is located near the park entrance. Here you can watch a great park film and see some cultural exhibits. You'll also want to visit the Denali Bus Depot, as private vehicles are not allowed down much of the 92-mile Denali Park Road, the only road in the park.
You can choose between a narrated bus trip (considered a tour bus) and a non-narrated bus trip (considered a transit bus). Obviously, the transit buses are less expensive and more flexible. You can get on or off almost anywhere aloing the road to experience the park on your own. You can purchase a ticket depending on how far down the road you wish to go. Note that the transit busses do stop for a restroom break and for any wildlife viewing opportunities. The longer you ride and the deeper into the park you go, the better chance you have of seeing wildlife. It's possible to see large wildlife roaming freely, such as grizzly bear, caribou, and moose.
The tour buses are more expensive, but you will get a detailed narration during the ride. You'll typically have the same scheduled stops as the transit bus and you can choose how far you want to go when you buy your tickets. The shortest round trip is 4.5 hours, but you'll want to at least do the Tundra Wilderness Tour to increase your chances of seeing wildlife. This is an 8-hour round trip. The full Kantishna Tour clocks in at 12 hours. Don't worry, these tours will usually come with a snack or lunch. If you want to learn about the park or only have one day in the park, the tour bus is the way to go.
I highly recommend visiting the sled dog kennels to see a ranger-led sled dog demonstration. You will also get to meet and interact with the beautiful pooches. A free bus will take you here from the Denali Visitor Center. If you want to walk, Rock Creek Trail connects the Denali Visitor Center and Murie Science and Learning Center with the sled dog kennels. Although it is a 2.4-mile one-way trip, it provides stunning views of Mount Healy. A slightly shorter but steeper way to get to the kennels is the Roadside Trail.
For hikers, the Savage River area offers beautiful trails. Savage Loop River Trail is a 1.7-mile loop that sticks near the river and has little elevation rise. McKinley Station Trail connects the Denali Visitor Center with the Riley Creek Campground. This 1.6-mile one-way walk brings you by historic building and railroad remnants. Also departing near the Visitor Center is the lenthy 9-mile Triple Lakes Trail. This has 1000ft elevation gain, but offers beautiful lake and spruce views.
If you take the bus to the Eielson Visitor Center, backpacking and mountaineering opportunities are available. Just remember that the weather here is extremely unpredictable. I have been unable to see the largest mountain in North America when it was right in front of me due to snowy, low visibility conditions. And then later, it was clear as can be. If visiting in the winter, enjoy fun activities like mushing and hoping to catch a glimpse of the Aurora Borealis.
While there is no park-operated lodging in the park, there are a few privately owned remote lodges in Kantishna that sit on inholdings within the park. There are six campgrounds, however. Riley Creek is the only one open year round and is by the park entrance. Further down the road, you'll find Savage River, Santuary River, Teklanika River, and Igloo Creek Campgrounds. They are all open in the summer, although only Savage and Teklanika allow RVs. Way down Denali Park Road is Wonder Lake Campground, open to tents in the summer.