I wish I had seen this post sooner. You are no doubt there by now. The Ansel Adams Gallery in Yosemite Village should have a good selection of film. I said should because it has been a few years since I was there. I hope they still have a good stock. Yosemite is a wonderful place any time of the year but especially in spring.
Ditto. You can get 4x5 film in the park. It's probably a bit expensive, but at least it is there. Be sure you check out the expired film in the fridge too. They may have some 4x5 in there.
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."