Subject: RE: Info on US national parks
I did a search and came up with the following... it may be what you are looking for.

Chris in Pearland, TX

A one-time $10 fee for a lifetime pass, purchased in person at a park gate gets you into any national park that charges admission, if you're 62 or over. And anybody in the car with you gets in free. Ask for the Golden Age Passport. 888-467-2757 or