Versailles skip the line?

Skip the line tours skip only the ticket line. There is no way to skip the security line, which can be a long wait, and is why early arrival is recommended. Visiting Versailles involves a lot of walking, especially if you go by train from Paris as it is quite a walk from the station to the Palace and the worst of it is the long walk across huge cobblestones once you arrive at the palace grounds. A guided tour by coach will let you out at the grounds, but you will still need to walk across the cobblestones.

If walking is an issue, I suggest you take a cane along. It will help you in Paris where the pavement is often uneven, as well as help you secure a seat on buses, and even elevator rides in museums, etc.where they are often reserved for disabled.

Reserve the King's Apartment tours and you don't stand in the long security line but enter at a different door. You can book them if they are still available on the official website. After the apartment tour which won't be crowded you will be in the jam packed main chateau which is everyone crushed together in lock step. You can be near the head of the crush by simply arriving about 45 minutes ahead of the palace opening time; then you stand in line for 45 minutes of course. Versailles is a fairly terrible destination for someone with walking issues and not particularly pleasant for young kids. Your odds of getting a golf cart are very low; the demand far outstrips the supply and by the time you finish the Palace there won't be any (probably)and a long line waiting for them as they are returned. It would be a good way to see the gardens if you can get one. There is a shuttle trolley sort of thing that goes from the Gardens over to the Trianon and Hameau if you have an interest in that.

Both Vaux le Vicomte and Fontainebleau are uncrowded and offer a more pleasant chateau experience but of course seeing Versailles at least once is pretty cool.