Re: We leave in 3 days. A few park touring questions.
Leaving in 3 days! Cool!!
Your list sounds great. I carry my camera, cigarette pouch(chapstick, nail clippers, change),film, baby wipes, tylenol, ponchos, and sometimes cracker snacks. All this in a bright yellow backpack.
Never having been down there when you needed layers of clothing, I can't really help, except maybe tying your sweatshirts/jackets around your waist instead of carrying them.