Rory:

Rory,
I saw tht you left a comment on my blog, but no mail to reply to.
We had cycled a long way before May, some 2000 miles - a mixture of here, Spain and some weekly sportives. We had only one 100+ ride before the event.
We had a mixture of bikes, with a triple being the front set of choice, though I never struggled too bad on a 50-36 compact.
If you send an e-mail to delomac@aol.com, I will send you route details, stopovers etc. I advise you have company at least, if not a support - thsi helped masively.
Brendan