Paris to Loire Valley

Most would agree.. an overnight( or two or three) is ideal to visit the area.. and a rental car( public transport between Chateaus is poor.. and not timely.

I would take the train from Paris to Tours or Amboise.( about an hour) . and rent a car there.. avoiding driving in and out of Paris myself.

My favorite chateaus are of course the well known, Chenonceau. Cheverny and Chambord.. all of which you could see in one FULL day. There are of course many more to see.. but if you only have one day...

I would google "Chateaux of Loire Valley".. check out the photos and historical information on each.. to see which two or three seem most interesting to you.. and then plot them out on a map.

Its a lovely area..

Years ago, we took a train from Paris to Amboise, then rented bicycles to get to Chenonceau, as well as to see the chateau in Amboise and the town itself. Even if you don't wind up with bikes yourselves, consider using the train to get to Amboise or another Loire Valley town, then see if you could pick up your car there. That could save dealing with Paris automotive traffic.

See related answers at https://community.ricksteves.com/travel-forum/general-europe/france-italy-trip/replies/new.

Thanks for the great advice. Looks like we may do the main chateaus you mentioned and do 1 day since we probably will stay in Paris all 5 nights (got a hotel deal for 4 days + 1 free). If we choose to do the 1 day tour would you still recommend renting a car or taking the TGV to these other sites?

You cannot take the train to the "other sites". The chateaus are spread out.. miles and miles from each other.

Suggest you take the train to Amboise or Tours.. then take a tour with a small tour company .. ( that way you can likely see more then trying to rush to drive to multiple chateaux in one day) or go ahead and rent a car.. there really is no other way to tour the valley on public transport.. there are some buses.. but they are infrequent and very winding and slow ..
Acco Dispo is well reviewed and runs tours out of Tours or Amboise.

Or blow the big money and take a bus tour from Paris.. I actually did that once when I was alone with a child and didn't want to drive. Pariscityvision and Francetourisme both are reliable.. Francetourisme is usually a bit cheaper. Both will be fine if you don't mind a long day and spending more then DIY.
The best trip I took there was however with a rental car and a few days.. just saying.. lol

"Let's just take the TGV to the other sites."
This is not a good idea, for the reasons explained above.

I would not try to see all three chateaux in one long day. You will have chateau overload. Pick two and see one the first day, spend the night in Amboise, and see the other the second day. My vote would be Chambord and Chenonceau, but your mileage may differ.

If you want a video preview of some of the most famous chateaux of the Loire Valley, here's Rick's new video on the area: http://www.ricksteves.com/watch-read-listen/video/tv-show/season-8/frances-loire-chateau-country