Just come!
Chances are you will get a permit. Someone is always canceling or not showing up. The worst...and it could be best,thing that happen is you go to your Plan B. What I've found is the Plan Bs can be a lot more interesting.
As for San G, that may be your bigger problem, if your plan is walk in to get a permit on the weekend. It's usually sold out well before the ranger station opens on Saturday or Sunday...that is if your plan is to utilize the Vivian Creek Trailhead. If your plans are for a weekend, go to SWGA fill out the permit application a fax it in.
