Catching bus from Geneva airport to Chamonix

There are some missing parameters here which makes it difficult to answer your question.

1) Are you checking luggage or just carryon?

2) Are you on a single ticket for the entire journey or separate tickets for the 2 legs?

3) Will your AMS-GVA flight land on time? No one knows the answer to that question. And
how far back in the plane will you be sitting?

If, for instance, you are on 2 tickets and checking bags, then you may have to enter the EU
in Amsterdam to claim your bags and recheck them on the second flight. Which means you
would have to do the immigration thing in Schiphol. That risks your connection but means you'd
exit Geneva Airport pretty quickly.

The other extreme is that your flights are all on a single ticket, you have carryon bags, and your
flight lands on time. The Geneva Airport is not all that large and the bus pickup area is a 2 minute
walk from where you exit the baggage claim area (but you pass bathrooms, so a 5 minute walk).

Even in the best possible scenario, since you have no idea of whether your flight will land on time,
I'd say 60-90 minutes as a pad. In the worst case, grab a coffee.

There are 3 different bus companies that service GVA-Chamonix. Whichever one you choose, have
the schedule handy, as the daily schedule is not uniform (I.e, not every hour) and you may want to
choose the company that gives you more options.

Our bags will be checked through, so it should be just a matter of picking them up. We are scheduled to land at 4:30 pm.. would be nice to get the 6:00 bus with the next bus not leaving until 7:30…

It only takes a little over an hour to Chamonix so even the later bus shouldn't get you in too late.

Which means you would have to do the immigration thing in Schiphol.

Isn't it standard procedure to go through immigration at the initial point of entry?

brain cramp, you're right, markcw.

Forgot to add earlier - worth checking what the policy is for catching the bus after
the one you were booked on.

GVA is tiny; got there on 1 Sept and bought my ticket on the way from baggage claim to the bus area. Including passport control (pre EES) and retrieving my bag (direct Air Canada flight) it took me less than an hour to get to where the buses are (last year they were not in their normal spot dut to construction).