Walkers touch a lot of surfaces in any given day, including other people they meet on the walk. While there are hygenic cleanser packs outside the porta-potties, it would not hurt at all to tuck a small container of purell into your fanny pack to use at rest stops, before and after meals. These can be found in any drugstore, small enough to buy one for each day of the walk. -- along with small packets of kleenex.
Please also keep your hands away from your mouth. And cover your mouth if you start to cough. Finally, if you have a fever or do not feel well, please skip the heroics and visit the medical tents that you'll find in any pit stop or back at camp. The gathering of folks is large enough for everyone to practice the basic etiquette of flu prevention.
That being said, look for me to get some great photographs of the walk and post them here.
If you'd like your own copy of this poster, google "Seattle King County Public Health" and print it from the home page. The site is packed with good advice and checklists. Or you can read more about flu preparedness most any day on the "In the news" section of www.anniesearle.com.