Huttopia at Rambouillet has a nice, relaxed atmosphere. I camped there in 2007 and 2011 with the family. In 2015, I splashed out and hired a wood cabin for ten nights so we had a bit of luxury. I would have done the same this time but my eldest daughters GCSE results come out on the Thursday of PBP so I have booked a big pitch for PBP week and the family are staying at home until the Friday after PBP. I'll probably book a cabin for that second week.
Regarding parking, there has been the option to book parking for cars or motor homes when registering for the PBP the last few times.