I'm back home now, this is the book I have, coincidentally I'm thinking of a tour through there this Oct as well, not sure what will be open for camping?
I have the french edition of that book (probably an older edition) somewhere!
I once looked at the route east of Orleans and came to the conclusion that there were precious few campsites advertised on it at all. Being inland campsites may well be all closed in october.
The Eurovélo route going sw from Paris has maps available online, I was looking at them the other day. I will try to find the link. Eurovélo4 ought to be on line as well. After that print or copy the sections you want (it's in sections of wimpish length)
Edit: This guide may be of interest
https://eurovelo3.fr/juin-2016-parution-du-guide-tours-cote-basque-a-velo/ This is only one page from the Scandibérique web pages. the home page is :https://eurovelo3.fr/la-scandiberique/ click on L'itinéraire in the bar at the top gives you the route in sections and each section has a map attached. I haven't yet looked for gps tracks, it not being my thing!