My wife and I went on 17 day trek through the Rockies and into Yellowstone.
WE hit 9 parks in all and could have seen even more.
One thing that we found was that seniors can buy a lifetime pass for only $10. It is good for all National Parks.
After going through a few of them we saw the prices charged per car...$20-$50.
The senior pas saved us a lot. Now, don't think you can borrow one form Mom and dad...The person on the pass will be asked for an I.D. and they ask at every park we went in.
This Bull was in Estes Park. He was around a home with his Harem of about 20...it is breeding season and he was watching them very closely.