The religious pilgrimage. They're a major part of many religious people's lives and have a long tradition in literature going back to the Canterbury Tales and further back. They can be a great basis for an RPG campaign as well. But how do you do that? Well, Skirmisher Publishing is here to help with their In the Footsteps of Herculese supplement.
From the website:
In the Footsteps of Hercules is a system-free sourcebook devoted to a pilgrimage trail that can be used in conjunction with any fantasy role-playing game. This book describes the various sections of the trail and the prevailing terrain and conditions associated with them; how most pilgrims travel them; alternate ways some pilgrims choose to approach the trail overall or specific parts of it; the things they generally hope to accomplish along the way; and things they might encounter on it.
There are many ways this book can be used and enjoyed. One is to simply read it as a work of fantasy fiction inspired by the myths, legends, history, and geography of Greece. Another is to use it as inspiration or a model for pilgrimage trails in your own stories or role-playing game campaigns. Yet another is as a setting for roleplaying game adventures of various sorts.
This book was created as a specific example of a Pilgrimage Trail, one of the 85 general sorts of places that appear in Skirmisher Publishing's Adamantine-bestsellng City Builder: A Guide to Designing Communities. As written, this trail is dedicated to the titular demigod and is set in a Dark Ages fantasy version of the Peloponnesian Peninsula of Greece and located within the company’s Swords of Kos Fantasy Campaign Setting. It can easily, however, be dedicated to any other appropriate deity or cause and dropped into virtually any other existing milieu and has deliberately been designed to be compatible with any of what Gary Gygax used to refer to as “a traditional fantasy campaign setting.”