Whatever you do avoid the parks if there is the remotest chance of kiddybumps being off on some kind of holiday. It was total bedlam last week.
Unfortunately, not having children, I didn't realise until too late that both Britain and France were on 1/2 term. The queues were horrendous, even for Fastpass and you were permanently on pushchair watch because some folk seem unable to drive the things without mowing you down or taking an inch of skin off your legs.
I had a great time, nonetheless, but I would still make sure I didn't go during any sort of school holiday period.