I had pretty much the same schedule last August. Drove up Saturday morning to Rock Creek to acclimatize/hike. Back down to Lone Pine for motel Saturday night (planned). Sunday day hike up at Horseshoe Meadows towards Trail Peak, planned to camp up there Sunday night; massive T-storms came in while back down in Lone Pine for dinner, road ended up closing, had to get a motel last minute. Monday night slept in the car at the portal no problem for 3am start too. Was pretty quiet after 9pm with the occasional hiker still coming down until about 11pm. Regarding sleeping around Yosemite, I've arrived late at the park and slept in the car very quietly with 4-5am wake up time, and wasn't bothered.
