I am planning to make a last minute trip up to the Portal on Friday night, Sept 18th. I see that no camp sites are available.
Where can I find the process for getting a walk-in site?
Hikerneil,
You should be able to find a one-night spot at the walk-in sites (these are not the drive-to camp sites that are in the reservation system.)
Here's
a thread on the walk-in sites, with a good map.