I have been to Versailles an insane amount of times ( over many many years ) .. probably over a dozen times now..
A tour is a rush job and they never allow you enough free time to really explore the huge grounds and all the other buildings.. and that part is really really worthwhile..
The palace will be crowded.. it always is now ( I have a photo of my first visit.. back in the 70s.. and I was about one of 10 people total in the Hall of Mirrors.. now a days .. its elbow to elbow masses. I love the history.. so always go through the palace anyways.. The Kings Apartment tour is a GREAT idea.. you get to skip the line ( you have a time slot) and you get to go in a small group ( of about 20) into areas of the palace closed off to the rest of the public.. Book this direct and online on the Versailles website.. its not difficult. . boo well in advance to be sure to get in.
I have also done the Fat Tire bike tour once.. a friend who had never been to Versailles wanted to try it.. I enjoyed it .. my friend felt very satisfied with what we saw.. I knew we were in fact missing stuff.. but since I had been before I wasnt too upset by that.. and as I said she was fully satisfied ( but she is not a history buff at all )
I normally just take the train.. as said.. its easy fast and cheap ( about 4 euros each way and about 45-50 minutes) from Paris, it is super easy to walk to palace and you wont get lost as hundreds will be walking with you.. lol
Arrive with tickets in hand , or museum pass.. do not go without .. as there are two seperate lines.. one for tickets and one for security.. and so you would have to wait in a long line for a ticket.. then get into seperate long line for security.. the Kings Apartment tour is great in this way as you can skip both and go to a seperate entrance.