In the summertime, your best bet is to make reservations well in advance of your visit. Spaces fill up early for lodges and cabins in the tourist season June-September. Food Groceries are available in the Valley at the Village Store, Curry Village Store or Lodge Store. It is much cheaper to buy groceries in Oakdale, Merced or Oakhurst on the drive to Yosemite. There are a variety of restaurants in the Valley that serve everything from pizza and deli sandwiches to the spendy stuff at the Ahwahnee Hotel.
Laundry is available at housekeeping.
You can get climbing instruction, arrange for a guide, and also rent gear from the Yosemite Mountaineering School and Guide Service . There are also a variety of climbing shops in the San Francisco Bay Area where you can purchase gear. If you are coming from the East Side of the Sierra, then you must visit Wilson's Eastside Sports which has an extensive selection of rock climbing and mountaineering gear. Bears have damaged cars for as little as a stick of gum or an empty soda can. When bears smell food, even if it's locked in your trunk or glove compartment, they shift into high gear.