Train from Paris to Chamonix, Chamonix to CDG airport Paris

Can we assume you are flying out on a Monday and spending Sunday night at one of the CDG hotels?
The fewest changes seems to be 3, one at St Gervais where you switch from narrow gauge to standard gauge train, one at Annecy to switch to a train to Lyon, then you can get a TGV direct to CDG.

Any routing noted TGV RER means you would need to switch to the RER at Gare de Lyon in Paris. This would also require you to switch from the RER A or D to the RER B at either les Halles or Gare du Nord. You might want to avoid that routing.

Even if a specific connection/configuration is listed as running 4 days/week, the other days will have similar options. Could be 2 minutes different or could be any little thing that makes it officially a different schedule. How to Look Up Train Schedules and Routes Online gives you the DB train schedule link and tips for using it. Once you get an overview of schedules, then do click the arrow for more details, such as connection points.

We traveled to Chamomix in 2013. We traveled from Paris to Beaune and stayed several nights. From Beaune we traveled to Chamomix. This was quite a lengthy trip. We took the high speed trains initially but as you get into the mountains the slower trains are your options.... Making many stops. The trip took up most of the day at least 6 hours.... Good luck.

The fastest way to Chamonix is by shuttle bus (AlpyBus et al) from the Geneva airport.

Thank you all for your helpful information. This forum is wonderful.