Since you'll be in Yosemite, you should stop in Groveland. The cafe there has wi-fi if you need to check in. There are two caches in town as well, one at the park and one on/near a bench on Main St.
And hey, if you stop at the pharmacy in Groveland, tell Jeannie HI for me (you haven't seen her in years but thats my aunt). Wave at my Grandparents when you go through LOL.

Have fun!