Looks like OP is there now, but for the benefit of others, I'll throw in my two cents!
Some kind of rain gear, no matter what the forecast says before you go. The dollar store ponchos are garbage. In fact, ponchos in general are tough to work with and uncomfortable. We prefer a good quality rain jacket - I have a Columbia one, DH has a Nike one. They fit much better and keep your dryer than a poncho, and they are more comfortable to wear. They also are easier to dry out to throw in a bag or can be tied around your waist. I prefer the types of jacket with mesh interior that have underarm vents. We also bring newspaper and two pairs of sneakers. If it rains, the newspaper gets stuffed in the wet sneakers. We'll wear the second pair, and the wet pair is usually dried out by the next morning.
Mole skin is a must for blisters. I have a little clear plastic bag where I keep items for anything that can go wrong - Pepto, advil, neosporin, cortisone cream, small sewing kit, eyeglass repair kit, band aids, saline spray for the nose, cold medicine, nail clippers/file, scissors. Might seem like a of stuff, but it doesn't take up much room and I have had to tap into it more than once.
