Versailles quick trip ticket suggestion help

I'd take 2 pm and then go early and do the gardens with the Fountains running -- they run briefly in mid morning and late afternoon (althought these things change all the time so check) See the gardens and fountains, get lunch at one of the restaurants at the foot of the gardens then come back to tour the chateau at 2.

here was our trip for just the fountains.
https://janettravels.wordpress.com/2016/02/15/fountains-of-versailles-a-little-chaos/
So you can get an idea of what that is like.

I wouldn’t count on buying tickets on the spot early that morning. Like Janet says, I would go for the 2 pm tickets while they are still available and do the gardens first.

If you start your exploration around 7 or 8 am, most of the central Paris attractions can be visited and photographed and done by lunch time just using the Metro to hop from one to the next, if all you're after is the photo op next to them. That leaves you the rest of the afternoon to just relax, maybe a stroll along the Seine or a sidewalk cafe experience, etc.

Just learned the hard way that once you are in the palace, you can't exit to the gardens, and most of the on-site dining is in the gardens. They also close at 6, so definitely do the garden, Trianon, and anything else outside the palace before your 2:00 entry. Four hours is plenty of time to tour the palace itself.