Swiss Alps

Debbie, Zermatt is only accessible by train. You cannot drive there. It is at the end of a long valley, but I would not call it hard to get to.

I can't find anywhere called Chamley, in France or anywhere else. Do you mean Chamonix?

You can look up trains from Chamonix to Zermatt on the SBB (Swiss Railways) website: https://www.sbb.ch/en
It takes 3h57 and there are hourly departures.

How are you getting to Chamley/Chamonix? That may affect your choice of further transport and destinations.

Edit: I've just found somewhere called Chambley-Bussières, population 428, in the Meurthe-et-Moselle department in north-eastern France. Obscure, is that it?

It is not hard to get to Zermatt by train. In fact, it is the only way to get there. If you have a car, you have to park it in a pay parking lot in Taesch and continue by train. In Switzerland, there is at least one train every hour in each direction, so waiting is not an issue either.

Edit, Maybe Chambley, France, near Metz. Big balloon festival there this summer.
http://www.hotairballoon.com/Lorraine-Mondial-Air-Ballons/

Chris F, sorry I did misspell it. The hot-air balloon festival takes place at the Chambley airfield in the département of Meurthe-et-Moselle in Lorraine, west of Metz.
My husband, 17 years old son & I are staying in Metz for 2 nights before starting our travels towards the Alps. Someone has recommended visiting Chamonix. Our travels have us flying into Paris at the end of July where we will stay a couple nights before heading to Metz. We will stay in Metz for 3 nights. I’m looking for ideas to fill another 3 or 4 days after leaving Metz. E fly into Paris but may opt to fly out from somewhere else closer to the Alps.

Offhand, Zurich is probably your best bet for a return flight if going to Switzerland.
Best connection to Zermatt is 5 3/4 hours. Trains to Mulhouse, then Basel, then Visp, then Zermatt. It is actually a longer trip with more train changes to Chamonix.

I found the balloon festival from Sam's link. How are you getting from Metz out to the airfield where the balloon festival is?
Not an idle question, if you are hiring a car (either in Paris or Metz) then you need to plan where to return it, and that needs to be somewhere in France if you are to avoid expensive surcharges.
If you want to end up in the Alps, it then makes sense to fly out of Zürich instead of doubling back to Paris.

With a 17-year-old I guess gobsmacking mountains will tick the box. In which case I recommend (as always) the Jungfrau region of the Berner Oberland.
This has 4 locations: Mürren, Wengen, Lauterbrunnen and Grindelwald. These have different characters, Mürren and Wengen are smaller car-free locations half way up opposite sides of valley. Lauterbrunnen is in the bottom of the valley and Grindewald is a larger location in the next valley.
This website gives info and hotels for all 4: https://jungfrauregion.swiss/en/summer/
I suggest you google all 4 for photos and reports.
All 4 are reachable by train (from Metz and onward to Zürich airport)

As above, look up trains on the SBB website: https://www.sbb.ch/en

My husband, 17 years old son & I are staying in Metz for 2 nights before starting our travels towards the Alps. . . . . We will stay in Metz for 3 nights.

2 or 3 nights?

Thank you so much for all the info. I was planning on getting a rental car in Metz. That’s a good thought on avoiding surcharges by returning it in France. I’m starting to wonder if we should just look at Chamonix to keep our cost & time down and plan a trip to Switzerland sometime in the future. Sounds like the travel time is starting to add up. From looking at the Rick Steve’s travel pages, Chamonix looks pretty amazing with lots to do. Any thoughts? Thanks for all the responses.

Exactly what I was thinking! And I am Swiss!