I highly recommend the versailles small group trip. The palace and gardens are marvellous and the guide was very helpfull and gave us a lot of good information about the palace and also about Paris in general. I would suggest a whole day trip since there is a lot to see.
The tour was very interesting as it gives background and context to the paintings, so that even those who are not that much into art, appreciate the works of art. One suggestion though would be to spend slightly less time on each painting so that there is more time left for the individual to have a quick look around the gallery on his own.