Your local travel agent will be a good source of information for accommodation, flights, car hire and other basic travel information but they may not be familiar with the Provencal legends of Mary, Martha and Lazarus.
Note: Be careful when searching the internet for 'Mary Magdalene tours provence' or similar, as many of the tours offered on the internet are geared towards worshipping Mary as a pagan goddess, as per the modern cult begun by 'The Da Vinci Code'. Avoid these types of tours at all costs!
Here are some links to reputable tour companies and guides in Provence who can help you design a customised tour of the sites mentioned in the book.
http://www.wellarrangedtravel.com/
http://www.taxi-provencetours.com/private-sightseeing-provence-tour/customized-tours.html
http://www.tours-in-provence.com/
http://www.avignon-et-provence.com/
