When we visited about 10 years ago we stayed here:- http://www.sandaya.co.uk/Camping/France/...isons-Laffitte/ and drove the 10 kms to Versailles. We found that by arriving at Versailles shortly after 8am which if memory serves, is about 45 minutes before it opens, there were plenty of good, safe car parking spaces.
We bought a "full visit ticket" at the gate which allowed us to visit the whole site and gardens and also gave us a fast track priority, thus beating the queues to the various buildings.
Before you go, make sure you pick a day when the fountains are switched on. At the time we visited, we were told that they are not in operation every day, just two or three days in the week.
What was good about the campsite is that it was a 15 minute walk to the town where there were many restaurants, but also had a train station that took us into Paris within 20 minutes. Because of this however, there was some train noise in the campsite although I notice from the website photos that they have planted many more trees which should deaden the noise.
It was fascinating to sit outside the awning and watch the constant traffic on the river as huge barges passed by.
There is an ACSI campsite near to Versailles but we've not visited it. http://www.campingcard.co.uk/france/ile-...sailles-103837/
Randa