So, the above map will form the basis for my ride and I'll probably join the route in the south west, at Narbonne. I've put it all in to the computer and it's a bit long for the time I'll have available, but if I cut two corners (ie I'll skip the bit on the top right corner that goes up to Paris - I certainly don't want to cycle through Paris anyway - and the spike bottom right that goes down to Marseille) then it's about right. I'll do some more research and see if I can use the exact same roads as the original race.