Ah sorry just seeing this! Yes there are campsites available and I believe you can camp in the backcountry as well. I spent the day riding along the park loop so didn’t do any hiking.
@Kusuma - it depends what you want to do! I decided to do the bus ride all the way out to see Denali. It’s a LONG ride. 5 hours each way. It’s cool though because along the way you see tons of animals and beautiful landscapes. To be honest tho if I ever go back I’ll probably spend more time hiking closer to the park entrance and/or do a climb on Denali.