As a voracious reader, I have the perfect analogy for the Challenge Walk. It has the feeling of picking up a great book where you laid it down on page 67 because you didn't have time to finish reading, and twelve months later having no problem picking up and starting to read again and enjoying the story even more than before.
That book is like the friends you make at Challenge. Twelve months later you just pick up where you left off the year before. A little older, a few more wrinkles on the "pages", but just as enjoyable to read and to share with friends so they can have the same experience as you.
The story has improved with age — just like all of us! You may have misplaced a book or two during that year or the one before, but you keep hoping they will turn up out of the blue. And if they do, you will be more than happy to open the book back up and start reading again.
Some of the stories are mysteries: who has a new boyfriend? Who has had a child? And, the best of all: what the heck was she thinking when she cut her hair like that?! Romance novels are spread around; new and lost loves will both be seen. Science fiction? Oh, most definitely. Quite a few fairy princesses, a few knights in shining armor who are ready to slay the MS dragon, and the occasional alien life form (I probably fall into this category) can be seen out there walking and crewing. (The best spot to search for the alien life forms will be at the rest stops along the way.)
For most of us who do Challenge every year, these books and stories that we see every year have become intertwined with the story of our own lives.