From Nice airport you can catch a direct coach to the village of Mandelieu 20 Euros and then from the same stop you can catch the local bus number 15 which is 2 stops and get off at the next at the camp site 1-5 euro. On return you catch the bus from the camp number 15 to the village, cross the road and catch the direct coach to the airport where you got off on arriving.
In the mobile home is a paper with all the bus's you can catch and where they go so if you like eloping you can do this with out a car.