Good questions Posi:
For the date change, we should be ok. The local crew will just get up there a bit earlier to make sure we have adequate room for a home base camp. The weather is up in the air, August probably still be a lot warmer, and September usually cools a little but not crazy on rain, however it may be rainy too... I'll do a bit more research on trends in last 5 years etc to check into it. The trail may be a bit busy still, but that can sometimes be a good thing as more people and parts to help when / if needed.
There is really not much hotel wise around. This is in the mountain ranges. There are some cabins around in Kyburz and Pollock Pines areas. They'd be about a hour drive on windy mountain Rd, but may be worth it to some. Where we normally camp, there is no electrical or water / plumbing hook ups, but in the area there are tons of campgrounds with these included. There are vault type toilets, and down the road are a few places with coin operated showers.
I'm planning to bring camp power by way of generators to have available for group use. I'll also be bringing a lot of camping gear for cooking and fresh water. I'll encourage everyone to bring their own water too, and we can get more if needed as well... More on that later. I'm also while there earlier planning to gather a good supply of fire wood for us if the fires are allowed.
All who are interested, google "Airport Flat Campground" in the El Dorado National Forest of California. Should be right by Loon Lake, and Gerle Creek Reservoir - North of Union Valley and Ice House Reservoir. For those not familiar with the area, its closest map huge landmark is west of Lake Tahoe.
Remember, when we do exit the Rubicon Trail, we'll leave through South Lake Tahoe too.
Lake Tahoe is about a hour and a half away from Airport flat is you take Highway 50 west from south lake Tahoe and go up the Ice House Rd turnoff from the highway. There are many hotels etc up that way if people get in earlier etc.
Posi is right though that the timing to find lodging before will be harder the longer you wait. You can check out Ice House Store on google, but it's hard to get answers from them...
I'm not good with Air B&B or whatever to see what's around in Kyburz etc, found few so I know there are options...
Remember also, if you like camping / have a camper your bringing, we'll be in the mountains already having a good time, so if you're early, come on up the mountain and join us. cool lakes to explore / fish, and swim in etc. Nice hiking and jeeping trails everywhere.
Or those of you that know each other meet up earlier if you want in Lake Tahoe, especially if you haven't seen / visited before. Nevada side gambling is legal, large hotels in South Lake Tahoe, - Lots to do either way.
I know some already have expressed they'll be around earlier too. So far I've taken off 9/3 through 9/18 from work (little over 2 weeks) to ensure I'm around for anything needed even after the official trip - keep in mind for those interested, we're thinking of doing some extra wheeling after the Rubicon week.
241 days until official start so far!
- joke... no rolling please! 
