2-3 nights outside of Paris

Besides the Loire Valley and Normandy, where else did you look? I don't want to suggest some place you have already eliminated. I love Provence but I think July is not ideal because it might be too hot for a lot of walking, hiking, and biking and this is from a person who loves to be warm. How about Brittany? I'm not sure about the wine options there but I know two French families that have their summer homes there.

The Champagne region is a quick 1.5 train ride from Paris. Some great biking there. I love places with rivers and river activities.

There is Disneyland Paris and Jardin d'Acclimatation which are both cool amusement parks. There's a water park near Paris too. My friends who travel with similar age children loved the water park .

Colmar. Not relaxing, but the kids might enjoy EuropaPark in Rust, Germany. It’s not far from Colmar.

Chartres will fit the bill. It's only an hour by train southwest of Paris. In January 2012, I spent an entire week in Paris, but I wanted at least a night in a smaller town.

As expected, I toured the famed pilgrim cathedral, Chartres Cathedral, which was worth the time. Rick's guidebook has a ton of information on the cathedral; Malcolm Miller, a historian from England, hosts in-depth tours, but check to see if he is active. The town also has a great stained glass museum, which is near the cathedral. There is also an old palace near those two sites that once hosted Napoleon.

Beyond the history and culture, Chartres is a pleasant town. I saw two other cathedrals that were as interesting as the pilgrim cathedral. There are timbered buildings from the Middle Ages. For centuries, Chartres hosted a major washing industry.

And the town center is as charming as any small European town I have been to. I remember eating a dinner and then getting a cheese board.

I am told there is bicycling. I would have taken advantage of that, but I was there in January.

you can TGV to Dijon and Beaune, and bike around the many vineyards

Chartres has a light show in the summer.

If you are flying out of Paris, I would end there and put your 3 day getaway in the middle so there is no wasted day getting back for the flight home.

We have done St. Malo as a few day getaway from Paris -- they have a great beach and there is good public transport to towns in the area. It would be pretty crowded in July of course.

Thank you all for the feedback! We’ll look at all these ideas.

Take a look at Amboise. It’s a charming little town and easy to get to by train from Paris. Leonardo DaVinci’s home Clos Luce is very interesting and the grounds are filled with models of his various inventions. There’s a castle where King Francoise I lived and the chapel where Leonardo’s bones are buried. You might also be interested in the troglodite caves. There are several chateaus nearby and you can arrange for day tours at the Tourist Information Center. Amboise is one of my favorite places.

For a mid-summer trip I'd be mindful of the potential for miserably hot weather that could make outdoor activities less enjoyable. Areas near the Normandy and Brittany coasts are much less likely to suffer from protacted heat waves. You don't have much time, so I'd look at places not very far from Paris, which eliminates most of Brittany--a great place to spend time in the summer.

Something I wanted to mention for seeing in Chartres - the Maison Picassiette. It was the home of Raymond Isadore, a cemetery- and foundry worker, who covered everything with tiles he made from broken plates and other found objects. It’s truly one of the most astonishing works of outsider art I’ve ever seen. I walked to get there, but a city bus is also an option.

Chartres or Britany- Dinan, St-Malo.

I don't have much to add to this conversation since there are literally hundreds of possibilities for the OP and the ones mentioned all seem fine. But since the Maison Picassiette in Chartres was mentioned and I just responded on a thread about Chartres where I provided a link to the tourist office website that mentions this place then below is a link to learn more:

https://www.chartres-tourisme.com/explorez/maisons-remarquables/maison-picassiette

I would agree with acraven that in order to beat the heat in July you might be better off to go to the coast, like Normandy or Brittany. Normandy is a little easier to get to. Bayeux is a cute little town with a great tapestry of the Norman conquest, and a good street market. The train station is not far from the town center, and if you do not want to schlep your luggage you can get a taxi. Peter

I think we've settled on Le Touquet, as recommended by a family member. It sounds easy to get to and fairly relaxing. Any thoughts?