We walked the first section of the GR4 in April this year. I know the following info won't be useful for you but other members might like a look at my blog:

http://livetowalk.wordpress.com/

which features the GR4 Grasse to Entrevaux section. I shall be featuring Glyndwr's Way next.

We're setting off on the GR5 in August (Lake Geneva to Chamonix section) and although we could find the route book, getting hold of a map was a nightmare. However, we did manage eventually. Perhaps you could try contacting the country's tourist board as it's certainly in their best interests!

Having walked the GR5 before, I found it incredibly well marked, but going without all the necessary info would have caused problems, particularly as the well we were relying on for refilling our packs had dried up and we ended up walking miles off course (with the map!) to find a lake to refill.

Unfortunately the map did not show the location of the HUGE cows with the NOISY bells that managed to keep us up ALL night on the overnight bivvy......

There is a Cicerone book which may be useful - not sure how much it has been updated since its original publication in 1993 but it does state reprinted in 2009.
http://www.cicerone.co.uk/product/detail.cfm/book/114/title/walking-the-french-gorges

As the author Alan Castle is stated to be a Long Distance Path Information Officer of the LDWA, I would hope he is contactable - may even find posts by him.

I am hoping to hike the GR 4 above section in June and would be interested to find out if anyone has information on daily distances, maps, and hotels along the way so that I can the route. Any help and information, maps, ect would be appreciated. Please resond to the email or here. Thank you

email address: johnathona22@cox.net