Yes, it goes through the snow band below the summit pinnacles. Saw your message board post, this wouldn't give you an accurate depiction of what you will see in late August. I did it when snow and ice covered so don't have any rock info for you but I do know it is very loose, not sure you can really protect it. When I did Middle Sister, I ran into a guy and his dog who had just done North Sister. It should be loose ledges and no real climbing but I can't guarantee that. Good luck.
"So I was sitting in my cubicle today, and I realized, ever since I started working, every single day of my life has been worse than the day before it. So that means that every single day that you see me, that's on the worst day of my life."
--Peter Gibbons (Office Space)