National parks buy a pass and it will get you into all of them. You have to pay $25 dollars per person to get in Zion national park. Yellowstone is the same price to I think. Pass is $80 for the Pass.
I have a disabled son who we got the Access Pass for last year. In Denali we got 50% off the camping fee when I made the reservation 2 weeks ago, and she told us, we won't have to pay the $10 per head entrance fee either.
We'll also be taking my wife's sister and husband who live in North Pole. She said who ever is in your vehicle gets in under my son's pass.