OK
There are supermarkets in Mer and a hypermarket in Blois.
There is a bakery about 5 - 10 mins away (wlk or 2 mins cycle) However for early morning breakfast there is a campsite shop that maybe 10p more, but tbh who cares
On site Pizza is OK, bar is OK, Restaurant we have never tried.
THere will be cutlery in teh mobile, we usually take pillows and duvets as a) helps the kids sleep b) more comfy that what is on offer - they are likey to have shets, or take a few fitted sheets. Cots are usually a travel cot or a 'cot side' to create a cot out of teh sigle bunk bed.
For bad weather we found the area fab (although it depends just HOW bad!!) We love cycling and hired bikes and went for long rides, you MUST cycle to the Chateau de Chombord if you can. Stop at all the nature 'hides' and watch the wild boar and deer etc. They hire bikes on site with baby seats on the back, can't remember about helmets tbh.
Chateau de Chambord looks like a disney castle on acid - brilliant for kids, 365 chimneys or something!! You can spend a good few hours there pretending to be the queen, running up and down the amazing double staircase. looking out from the roof etc. You can also hire a rowing boat for an hour or two, have a meal or snack inthe coutyard, and lastly go to the Horse show. MY KIDS LOOVED THIS!! We spent a full day at the chateau and then went back for the horses.
Blois has a 'son et lumiere' or whatever show late at night with an english story on wednesday IIRC. Agian really lovely evening, take a blanket or two to sit on a wrap up in. Blois is pretty to wander round too.
We really like this site it is small and friendly and have been back again for a night travelling through
Further afield (Blois is 30 mins max) you have other Chateau, wine/champagne trails/zoos etc etc. I think they are all within an hour. Orleans is great IIRC (didn't go this time) with loads of Jean d'Arc stuff.