One of the main problems facing anyone wanting to 'follow in the footsteps' of medieval pilgrims is that we know next to nothing about their journeys. Few medieval people could write, and even those that could often left no record or, if they did, those records have since been lost. Or they may have written about what they encountered at their destination rather than which route they took or what they encountered on that route. Even where records do survive, because of their small number we cannot be sure that they are representative of their time; most of them are from the later Middle Ages - or, of course, post-medieval.
Fortunately, those itineraries we do have are increasingly available for free on the web, and the placenames mentioned can be plotted onto an online map where they can be consulted/amended/improved by anyone with an internet connection. This section documents those records we do have of journeys in medieval times, at least those in W and particularly NW Europe, and particularly those to Rome and Santiago.
Although some of the online records are scans of the original manuscripts, most are simple scans of printed transcriptions, often 19th-century ones that are no longer subject to copyright. Though not as nice to look at, these are generally more practical, as the printed text is easier for the non-specialist to read than medieval scripts; they are also often annotated, for example giving modern equivalents of placenames.
There are broadly two categories of itinerary, roughly like their modern equivalents: diaries of a particular person's journey, and more generalised guides, perhaps giving alternative routes. Although in principle, travellers were free to go any way they pleased, in practice, the obstacles of mountains and rivers channelled them into particular corridors, and the same broad routes crop up repeatedly. The relief map used here, with no clutter of modern roads and settlements, makes it very plain that medieval travellers largely kept to the main river valleys and the main passes - not for them the hill-walking so popular nowadays. These routes were the main roads of the time, and to a large extent remain the main roads today.