I just came across this information, which may be of help to those of us who wish to make reservations at Recreation.gov and have Senior Annual, Senior Lifetime, Golden Age, or Access Passes.
"Add your Senior Annual, Senior Lifetime, Golden Age, or Access Pass number to your Recreation.gov account. Sign up or log into https://www.recreation.gov/
. At the top right, select your name and select My Passes. Select Interagency Passes from the left panel. Enter your pass type and number under the My Passes section. This will NOT automatically apply a discount to your past or upcoming reservations. You must apply the pass information when booking future reservations due to individual facility policies."