I have no idea how I missed this before, but here is a link to TONS of free ebooks about all things Yosemite. I feel like a kid in a candy store. A free candy store.http://www.yosemite.ca.us/library/
I looked for the PBS one and couldn't find the full thing anywhere, only the preview.
I watched a BBC Scotland documentary about Muir (Last Explorers series) last night and it was pretty good. It was more about him than the park itself but it still had tons of relevant information. I'll try the Ken Burns one next if it's on Amazon.
I'm open to any forms of information, but after a long day of work and school, TV is the easiest thing to digest on weeknights, though now that I've found a bunch of ebooks I can put them on my phone and read in every little pocket of down time I get throughout the day.