So far our plan is:
Day 1 Early flight from Tampa to San Jose (or maybe LAX), rent car, drive to Merced, stay overnight in hotel (after gorging on In n Out Burgers, which, alas, do not exist east of Austin TX

Day 2 Rise super early, leave Merced, drive up to TM and get in line for Wilderness Permit. Question: For early September (i.e. on Labor Day) how early should I plan to try to get in line for the permit? Since I have no permit now and we're flying in from out of town going home isnt an option. Are people camping out all night for permits in September? If we need to be in line as early as 6-7 a.m., then when would y'all leave from Merced? Or would we be better to simply drive all the way up from the airport and try to get a campsite at White Wolf, Yosemite Creek or Porcupine Flat? My concern there is not knowing if campsites would be available in those campsites by the time we'd make it up the mountain (but leaving at 3 a.m. from Merced to get a decent place in line would be rough too). If y'all were in our shoes, what would be your best plan?
If we don't succeed in getting a permit on Day 2 I'm thinking we'd try to secure a campsite at WhiteWolf/YCreek/Porcupine and try again early the next morning, but is there another strategy or approach?
Also, I seem to remember that the road in to White Wolf campsites was pretty bumpy, and I'm not familiar with the approach roads for Yosemite Creek and Porcupine Flat. Since we'll be in a rental car (not a personally-owned SUV) which of these campsites would be our best first try based on campsite availability for Labor Day and type of road access?
We'd really appreciate any suggestions and tips you could share.
Thanks!