Something to remember... If you are of age (62) you can stop into selected US government offices,,,, or the web site,,, and obtain a senior pass, Now depending on when it is issued they have assorted names.
Some Government "Attractions" like the Grand Canyon the pass gets you a significant discount on admission (like 100%), and at many Government operated parks it gets you half off.. (NOTE: Some parks, like the RV park at the aforementioned canyon are NOT government operatored, they are vendor operated and vendors can decide if they will honor the pass, most do not).
So a 22 dollar a night site at one COE park I stay at, 11 bucks, Forest service park normally 15, 7.50.
I can take that.. ALas, the pass costs 10 bucks (see how fast you recover, one night) plus millage to get it
(I walked into the district office, handed the young lady my Driver's License and a #10.00.. She did not even need to ask why I was there).
I had to get my own in 2013,, used to use my wife's but here's expired in 2013, Easter Sunday in fact.