UPDATE!
Thanks for the advice! We went to Versailles today and did end up booking the Kings apartments tour after I posted the original thread. WOW that was a good call. We arrived just before 9am and the line was already out to the street and wrapping around. There was a quick bag check near the street that was fast, but then it seemed you had to get in the other line to enter regardless of ticketing... there was no other place to go in, ticketed or not from what I could tell. I don;t know what the deal was with that, but I am glad I did not have to find out.
We went to the guided tour office around 9:15 for our 9:30 tour, had bathrooms there with no line, and we waited on comfy chairs for the guide. She took us around it is was very interesting! We also went into the opera house. The mobs and mobs of people passing us by on the "other side" made me extra glad we took the tour.
We went back into the regular area after the tour around 11:30 and it was miserable. Just hordes of people shuffling along, blocking the walkways, and I didn't really think there was nearly as much interesting to see as there was on the apartments tour. I guess maybe if we had gotten there an hour before opening and been in the front it may have been bearable... but we could not get out of there fast enough!
We went down to the gardens and then into a little take out food place that was calm and had something to eat. We left around 1pm... we didn't go out to the Trianon part... just too tired!
If you do not arrive really early or have a tour- yikes! I think you can go to the office and try to buy a tour on the spot. Or else it seemed you could just pass the line and go around to the gardens... I didn;t see anyone checking tickets or anything as we left. IMO the stuff you saw on the regular tour was in no way worth the hassle of that line and shuffle of people. You could see the gardens, the outside, and I bet the Trianon stuff and be just as happy.
But the guided tour is definitely the way to go! No big line, good info and only 7 euro. I don;t know why someone wouldn't take it....
Thanks for the advice!
Kim