Rethink your planned time to arrive. I would suggest leaving the east coast the weekend before Thanksgiving and arriving that Tuesday or Wednesday latest. Stay until the Monday after the holiday and sticking to the I-10 to make the crossing to avoid any potential issues with snow or ice.
In September you will find empty dunes that are empty for a reason and in November you will find the dunes when they are at their best. Full of people who are willing to let you tag along on rides and who are doing the same thing you are doing. Camping 100% off the grid. We have a handful of pit toilets and that is all. Making it at that time of the year in a enclosed trailer is easy for 4-5 days.
Brawley is 20- 30 minutes away from the sand and like they have said it is a small town, Yuma is a bigger town but from Glamis is the better part of an hour or more and you get to drive on one of the worst roads you would ever want to drive on ( Olgilby) So staying in a hotel in either city is possible, it just makes your day pretty long and one of the great things about Glamis is the nightlife. Something that should not be missed. Now don't be looking for bars or clubs but there are locations where people go to watch the sunset and hang out and watch the craziness go off.
Let me just try and explain how dangerous the desert is... Four young marines with desert survival training got a wild hair up their butts one day and left the coast( Camp Pendleton) on a average day figuring how bad could it be they were in Iraq after all and were well trained. To ride dirt bikes for a few hours.
A thrown chain and a fouled plug later and three of the four were dead from exposure. The last one was found pushing his bike. Why he was pushing it was not clear that bike was fine.