I haven't gone from Los Angeles to Yosemite, but I have been from Fresno to Yosemite before.
Not that I would recommend gambling there, but the Chukchansi Gold Casino just south of Coarsegold has reopened. The buffet seems to be more expensive than I remember before they closed (long story). It used to be about $10 per adult, but now it seems to be double that.
Fresno or Visalia might be better places to stop for supplies. Oakhurst is actually a pretty small community. They have the previously mentioned Vons supermarket, as well as Raley's. Oakhurst also has a variety of local restaurants and fast food. There's also a CVS Pharmacy (really a variety store) in town. They also have one of the best restaurants in California, although I'm not sure if you're looking for that kind of thing.
https://www.yelp.com/biz/ernas-elderberry-house-oakhurst