FYI. Too bad I am not qualified. Hope you take advantage of your privilege here (I may beg to tag along, haha).
On August 28, 2017, the price of the America the Beautiful – The National Parks and Federal Recreational Lands Senior Pass increased for the first time since 1994. The lifetime Senior Pass will increase from $10 to $80.
The passes cover entrance and standard amenity (day-use) recreation fees and provide discounts on some expanded amenity recreation fees.
Are there any other benefits from a Senior Pass?
Yes, traveling companions can also enter for free. The Senior Passes admit pass owner/s and passengers in a noncommercial vehicle at per-vehicle fee areas and pass owner plus three adults, not to exceed four adults, where per-person fees are charged. (Children under 16 are always admitted free.) Also, at many sites, the Senior Passes provide the pass owner (only) a discount on Expanded Amenity Fees (such as camping, swimming, boat launching, and guided tours).
Changes to the Senior Pass (U.S. National Park Service)
America the Beautiful - National Parks & Federal Recreational Lands Senior Pass | USGS Store