Purchase 4-Day Museum Pass Across from Sainte-Chapelle
Spot Souvenirs et Services (5 Boulevard du Palais; open Monday–Friday, 7:30 am to 7 pm; Saturday and Sunday, 10 am to 7 pm), the small tourist shop beside Les Deux Palais Café, across the street from Sainte-Chapelle. This will be your optimum spot to purchase your 4-day Museum Passes. While one of you holds a place in the Sainte-Chapelle security line, the other can cross the street to buy passes. You may be able to able to purchase Sainte-Chapelle concert tickets here too.
The 4-day Museum Pass will be extremely valuable to you throughout your stay in Paris because it will: 1) save you money, 2) allow you to move to the head of the line at most museums and sights, and 3) remove the need to decide whether or not to enter a museum or other sight when you will have only a short time to visit. Your entry already will be paid for. 
With your Paris Museum Pass in hand, you now can skip the ticket office line at Sainte-Chapelle. But you still will need to go through security check. Ask about which line is which to make sure you are standing in the correct line.
Local Transport
For local transportation you will use the most interesting and scenic options available. In Paris, this means you most of your comings and goings will be by Batobus, traveling down the river towards the Eiffel Tower, then back up the river to your stop beside Notre Dame, hopping on and off along the way to visit museums, monuments, parks and neighborhoods.
By using the river as your main transportation route, instead of the underground Metro, the getting there will be as rich an experience as the arriving. Much of Paris is best viewed from the river. And by using the river for transportation, you will quickly develop a sense of which way to walk to get to the river, as well as which way, and which bank, you are headed to for each day’s venture—downstream or upstream, left bank or right?
You also will be using an occasional taxi (or Uber), plus one ride by Bike Taxi from Place de la Concorde to the Grand Palais and a ride up the funicular to the Basilica in Montmartre.
Also, you will be taking an evening cruise on the Seine the first evening of your stay. And you may opt to use the Metro on Day 4 and Day 5 instead of the recommended taxi or Uber.
Purchase your Bateaux Parisiens tickets in advance of your trip. Wait until you arrive in Paris to purchase your 2-day Batobus Pass.
Review your Day Pages before your trip so you will know when, where and how to make these purchases once you arrive.
Reservations
In Paris…
Purchase tickets to a concert at Sainte-Chapelle
Consider Attending a Concert at Sainte-Chapelle if at all possible. If you do decide to do this, purchase your concert tickets at Sainte-Chapelle before your trip. If you prefer to wait and see, you may be able to purchase them now at the Souvenirs et Services shop across the street from Sainte-Chapelle. But the space in the chapel is very limited. So tickets may no longer be available by that point.
Over 100 classical concerts are performed in the chapel each year, with starting times at 7 pm and 8:30 pm. . There’s nothing more ethereally stunning than to gaze up at the purple, ruby and blue glow of all this stained glass while listening to Vivaldi’s Four Seasons.
Make reservations for the Eiffel Tower
Eiffel Tower tickets for a specified time (€16.3 to 2nd floor. €25.5 to Summit: https://Ticket.TourEiffel.fr/ OR make dinner reservations for the 6:30 pm seating at 58 tour Eiffel https://www.Restaurants-TourEiffel.com).
Make restaurant reservations at least one day ahead
Review your Day Pages before your trip so you will know when, where and how to make these purchases once you arrive. For each day, the Day Pages in your Trip Guide will give you the specifics of your lunch and dining options, with phone numbers to call for reservations.
