Paris 9 Day Itinerary: Mom & Daughter Trip

You have a good list of sights in Paris, plus Giverny. Versailles could be another day trip but it wouldn't be "low stress and relaxing." For low-stress relaxing I'd suggest a day, or partial day, in one of Paris' great parks, like the Bois de Boulogne or Vincennes. Or you might like one of Canauxrama's longer cruises, like "Guinguettes on the Banks of the Marne." (I've been on a different ride with that company, but not that one.)

As for the sequence of in-Paris sights, use a map to group places you want to see, and try to focus each day on a different area so you're not charging all over the city every day. Take account of what days things are closed (usually Monday or Tuesday). Try not to combine two big museums, like Orsay and the Louvre, in a single day. Definitely take advantage of the Bastille Day celebration (I envy you that chance). A good guidebook can tell you enough to develop your own plan.

The Eiffel Tower is on everyone's list, but let me suggest that you consider the much-easier-to-access Tour Montparnasse as an alternative. A comparable bird's eye view of the city, including the beautiful ET and excluding the not-beautiful TM. You don't need to book ahead so you can take advantage of good weather. Most posters here would probably disagree with me about this, though.

Also, looking for easy and interesting day trip ideas from Paris. We are definitely planning to go to Giverny one day. My daughter would like to get out to the French countryside or to the coast. She's very active and loves to hike and explore. Any thoughts on a wonderful day trip that would be low-stress and relaxing?

You say hike, do you also bike?
If you do, my first thought to check the "countryside" box was a day trip to Fontainebleau and Barbizon.
You can take the commuter train to Fontainebleau, head to the Chateau, then bike through the forest (passing by the beautiful Gorge d'Apremont) on largely car-free roads to the pretty village of Barbizon and back. It's a moderately hilly 10 km one way.
Bike rental is possible in Fontainebleau, or also in Paris (but there are restrictions on carrying bikes on commuter trains in weekday rush hours).

The coast is possible as a day trip but it would be a long day trip. An option is the baie de Somme: you can take the train from Gare du Nord to Noyelles, and use the local Chemin de Fer de la Baie de Somme to explore either the Le Crotoy side or the St Valéry side. Bike rental is a possibility. I've only ever done this with a car, so you would have to check train times etc., but Paris to Noyelles takes just over 1h40 so it should be very feasible.
Étretat, with its famous cliffs, is also doable by train to Le Havre plus bus, but travel time would be longer - it's already 2h30 just to Le Havre.

Wow, great-sounding trip. You can see on the Paris museum pass website which museums are included, and get your museum pass at the first museum you visit. You’ll want to reserve a timed entry to the bigger museums (the Louvre, certainly), and do not need your Museum Pass in hand in order to do so.

Buy Rick Steves Paris guidebook 24th edition and take all of his self-guided walking tours; this way you'll see it all.

My daughter would like to get out to the French countryside or to the coast. She's very active and loves to hike and explore.

There's really too much to choose from, you might give her some options and see which sound best to her and then refine from there. France has a wonderful TGV network that can whisk you many places. See http://inat.fr/map/grandes-lignes-france/ And the inter-regional trains open up much more albeit closer in to Paris. Depending on how long a day you want I'd consider a ride of up to 2 hours reasonable (eg: leave 8am, start somewhere at 10am, spend the day, have early dinner at 6pm, return on 8pm train). There are also 2 books about this: "An Hour From Paris" by Simms and "Daytrips France" by Steinbicker.

Re: the Museum Pass

After you’ve decided it’s a good fit for you, you can certainly buy at your first museum if it’s one of the smaller ones such as the Rodin.

BUT since you are in the Rue Cler area I also suggest the Tabac on Avenue de la Motte-Piquet which sells both Museum passes as well as Metro passes. It’s very easy to purchase there even if you don’t speak French!

https://tinyurl.com/yc8eb5uh

https://tinyurl.com/yc5prdty

To Rue Cler area from CDG, I always take a taxi from the official taxi rank at the airport. It’s a flat rate into town and is currently 62E to the Left Bank where you’ll be located. If you take the train you’ll have to change at one of the metro stations which is a hassle with luggage.

What a fun time!