Do the white rapids raft tour the evening you get there if going to Denali for your first night. We had so much fun. We usually do only the float rafting trips but we tried this one and it was a blast. We had all ages on our raft. We are in our 40's, but there were 60 somethings and 70 somethings on ours and we had a blast. You just hold on to each other and enjoy the ride. The raft rides at amusements parks are much rougher than this one. They have you very bundled up in wet suits so you do not get wet.
We also did the Natural History 8 hour bus ride. We were somewhat disappointed in the amount of wildlife we saw. It is all in pure luck. The 3 hour bus tour that left right after ours saw more wildlife than we did. But they missed the huge mountain ranges. As our driver said they just saw the driveway of Denali National park.