This has been such a strange year for weather, all bets are off. Check the ten-day forecast before you depart, check the forecast daily, carry layers, weatherproofs, and poles. You could encounter anything from fine fall days to early snow.
Madame and Monsiuer will not wait around for you. Even if they are claiming in MMD to be open, if you do not reserve, they will take off and do errands or visit the grandkids. The French always call a day ahead, especially because they will tend to book demi-pension.