Reginald Farrer wrote a book about his botanical expedition to Tibet titled On The Eaves of the World [1]. In Volume 1 he wrote about what he packed:
... the rest of the year (1913) was spent in agitated ponderings over what must be taken and what might be omitted. ... to my own thinking, almost everything is omissible once one makes up one's mind to it, and it is wonderful how simple life can become when resolutely resolved into its bare essentials. In my own case, I find it reduces itself to the materials of washing and the works of Jane Austen; of the two, at extreme need, it would be the washing materials that I should jettison.
An American might not prize the works of Jane Austen so highly as that. Below [2] are example pack lists that i have collected.
Where i live, now these checklists are obsolete. The Rogue River National Forest has switched to only cashless payments for its campgrounds [3]. You pay using the recreation.gov app on your smartphone. You must also keep your smartphone on your person as proof of payment when the ranger patrols the campground.
Both to install this app, and to process your payment, you will need an Apple or Google account. This leaves digital detoxers on the wrong side of "You Can't Sleep Here" [4].
My favorite workaround is what i call "scratch camping," also known as "wild camping" [5]. But not everyone is up for purifying their own drinking water and shitting in a hole in the ground.
Here is another way it can work: Drive a mile past the campground to that turn-off in the road and set up camp there. When you do your morning constitutional, walk to the campground, refill your water bottle, use the toilet, then walk back.
Look ma, no Google!
p.s.
This is not about money. If it were, i wouldn't be complaining about Uncle Sam being unwilling to take my "legal tender for all debts". Recently i bought a topo map and a gift at a ranger station. What i resent is encroachment of corporate overlords on public land and recreation.
[1] On The Eaves of the World by Reginald Farrer
Volume 1[2] Example pack lists
Backpacker's Checklist