Check with your library. Most systems in the US have online catalogs you can check, and if your branch doesn't have it, they will can place it on hold and transfer it to yours for you at no cost. If they don't have it, ask if you can get it via LINK+ (an inter-library loan) from another system. This is also provided at no cost with most systems.
A quick internet search can get you in touch via chat, phone, or email with your local library and someone to help you find a book.
I work at a library and people reach out to us looking for books all the time. It's our job and we like to help people connect with information. Don't be afraid to reach out. We serve everyone from retired boomers, little kids, unhoused, and people with special needs all day long. It's a big club and you're invited.
For, example - in my county we have over 20 branches (big and small) and allow you to check out up to 100 books (ridiculous right?) free of charge for three weeks (that you can re-new) for twice for 3 more weeks each time. That's over two months to read a book! (I'm a slow reader too!).
Go get yourself a library card and use it to unlock the world.
If you want to continue in the vein of old timers, check out, "Walking Up and Down in the World : Memories of a Mountain Rambler" by Smoke Blanchard. I read it years ago, and it's really just a collection of writings of his memories. It jumps around a bit, but there are some good stories in there. His recounting of one of the Sierra's most famous early mountaineers, Norman Clyde, was interesting - he'd pretty much move into the Sierra high country each year and set up a basecamp for fishing, climbing, and adventuring. Lots of little adventures from the Himalaya to the eastern Sierra.
Also, going way back..."Mountaineering in the Sierra Nevada" by Clarence King - is another old interesting book about the early exploration of the Range. King was an abolitionist, unfortunately, some racist viewpoints of the author still pop up a few times. Read it in context - as a historical document of the late 1800's it features fantastical accounts of first ascents, being chased by bandits, etc.. If it was a movie it would be John Muir mixed with Die Hard. Lol
You could probably find an ebook of this one, as it is now in public domain. All in all I spent $1 or $2 on each of these at a used bookstore eons ago. I wouldn't spend too much on hunting them down, but I like reading history/old books too!
Thanks for the recounting of Colin Fletcher's book. Sounds interesting!