If you feel more secure by planning your route and stops beforehand, then use the internet to plan your stops. Most chains in France such as Campanile or Ibis give enough info as to whether they have secure parking or not. If you are a bit more adventurous then take a chance and start looking from around 5pm. Most French cities have large billboards on their approach advertising their hotels and most chains like this are around 30 to 40 euros for a double room. Preferably stick to the back roads or route nationale (N roads) and look out for the Chambre d'hote (bed and breakfast) signs. They will be more friendly, cheaper and being out of the towns more secure for your bike, plus you will feel you have enjoyed more of the "real" France. If I were you I would certainly think about booking a stop at La Rochelle as posted above. You can also go to the tourist information place when you arrive in a town and ask them to organize or recommend accomodation.
When we are travelling in France as a group we usually book in advance at somewhere like a Campanile, but on our own we drift where we fancy and start looking from around 4 or 5pm. Not been let down yet and I know which I prefer.
Enjoy your trip.
[This message has been edited by harleyrider (edited 17 March 2006).]
If you think you are too small to make a difference you have never spent the night with a mosquito.