That's great Hayden. We know that CR is your main objective, so everything is going to be about that and making it all come together, if at all possible.
As of yesterday, there have been a couple changes in the Full Trailheads Report. Entry at May Lake is no longer available for your dates.
https://www.nps.gov/yose/planyourvisit/ ... lheads.htmYou can still get to CR, but you're going to have to walk a little farther and reverse directions. As Bighead mentioned, you can enter at May Lake > Snow Creek with your first night in the area of Mt Watkins. That's a gorgeous area, btw. Your exit will be Sunrise Trail at Tenaya Lake. This route does give you some extra hiking back to the car (over 8 trail miles), or some hitchhiking that shouldn't be too hard.
The second option is to enter at Murphy Creek. First night at May Lake. Again, exit at Sunrise. At the end, this will only add less than a mile back to the car. What you'll do is go up Murphy Creek, walk about 6.7 miles up to May Lake, spend the first night there (09/15). From May Lake, you continue your loop for another 4.9 miles to the top of the Sunrise Trail and spend the second night up at one of the Sunrise Lakes (09/16). If you examine the route the High Sierra Camp (HSC) people hike, this is the one you'll also use. At this point you have the option of either maintaining camp where you are at Sunrise and day hiking to CR, or you can haul your packs with you and establish a new camp on the flats just below the north side of CR (09/17) . Either option will be fantastic, but with the second you will need to hike back down to the stream you crossed for water though. Also, if you do the second option at the north slope, you can first make camp, leave your packs, then day hike up to the summit that afternoon, and even again early the next morning for the sunrise. And if you're comfortable staying another night in the area, you can again on 09/18, considering that it shouldn't take you more than a few hours, tops, to get back to the car and drive back to SF for your flight home on the 19th. If not, you can go ahead and do your 3 nights and 4 fairly easy days on the trail, head back to the backpacker's camp in Yosemite Valley on that night of the 18th, then leave for SFO directly from there.
Apply for your permit for option 2 as your first choice, entry at Murphy Creek. First night: May Lake. Go ahead and state Happy Isles as your exit in order to have the run of the area (exit trailheads aren't enforced, but some look better than others for applications). Use May Lake > Snow Creek as your second choice. First night: Mt Watkins. Exit also Happy Isles. For your third, pick something random, but that you wouldn't mind as a backup plan (Ten Lakes Basin?). They'll either give it to you or not. We'll see what comes back within about a day. If you don't have one, get a map (Tom Harrison 1:63,360 Yosemite High Country). Whatever you get, spend some serious time familiarizing yourself with bear canisters and food storage regulations.
Good Luck!