Taxi Timing/Price

RER-C trains begin departures from Versailles Rive-Gauche station weekdays at 4:30am and Sundays at 5:30 am. That likely is cutting it too close for your timeframe on a Sunday.

If you overnight in Versailles, ask your hotel to arrange a taxi or use Uber for the transfer. At that hour on a Sunday a taxi should cost about €60.

Go to: https://www.g7.fr/en/book-taxi and do a dummy booking for a sense of the price. I have a Taxi G7 account and have booked a taxi from Versailles to central Paris so I suggest downloading their app and using them for the trip.
Edit: Or do as the first person to respond suggested.

Hi Demi,
For such an early morning trip I would either book an Uber in advance, or have your hotel order a taxi for the morning the night before.
I pre-ordered an Uber to get from Bievres (a town near Versailles) to Gare de Est this June. The Uber picked me up at 6;30am. We got there in plenty of time, no problems.
Have a great trip,
Cheryl

Sorry Demi,
I forgot to include the price. My Uber to Gare de l’est was 42 euros.
Cheryl

Hello,
Thanks to all who replied. I have decided not to stay in Versailles and instead stay in Paris.
Merci beaucoup

Demi, I think you are wise. Do what is simplest. If on a weekday I would say stay in Versailles, on a Sunday.....well........! Paris is a good decision.

Hi Judy,

Planning my trip i did a 180 and completely revamped my trip- originally was staying in Versailles with day trips to Mont Dt Michel and Paris....now flying into Paris and taking a train from the airport directly to Rennes and staying there a few days to see The Mont- then train to Paris for a few days before my train to Italy. It just made more sense as we really wanted to see Mont St Michel and have been to Versailles Palace before but wanted to see it again, we can always just take the RER from Paris for the day to see it again.

That's the fun of planning, asking questions on the forum, and then finalizing everything.

Well done, Demi!

I missed your smart update but I am going to leave this here for future planners trying to make a plane or train. Well done.

With a long distance and a high stakes trip I would arrange a cab with G7 on their English speaking line the night before and would add an extra half hour. Yes, you will be cooling your heels at a train station but you won't miss the train. Spring a couple of years ago, we had a train from Gare du Nord to Amsterdam and were in the 13th -- so not a huge distance. we are old and cannot manage our heavy luggage on metro stairs so booked a cab. I added that half hour much to the dismay of my husband about getting up half an hour early. It was pouring rain, traffic was at a standstill in central Paris. Our cabbie was aggressive and made full use of parking lots, and bus lanes to try to get us there and he did -- but barely -- although I had added a half hour to the reasonable time to get there, we were so late that we had to jump on the last car on the train and then make our miserable way down the narrow aisles to our car with our luggage. But at least we made it. Don't plan it tight with a google map estimate -- it always takes longer than it does.