You could use the link http://www.tpg.ch  and use the 'recherché d'itinéraire for finding out the public transport from the different villages to Cornavin or Place de 22 cantons which is 2/3 minutes away.
That way you can find out for the different parts of the day, because the coverage will vary.
Ferney Voltaire would probably be the best of the lot, as public transport in some of the frontier area that side relatively sparse. The buses also wind around several villages  in some cases which lengthens the journey.
Some of the distances are quite long and might  a problem if you wished to meet people in the evening/weekends in Geneva, travel back by public transport. These options could be limited.
This also for people wishing to visit you.
 
By car,  traffic tends to be  be pretty dense morning and evening commute into Geneva from border towns and even down from the border to the city centre at various peak times.
Hopefully someone  else  can add more details
 
TogJay, May 9, 2015 @ 23:51

I have never tried to drive to Cornavin in the rush hour, and I wouldn't recommend you do either.

IMHO, if you want to live in the Pays de Gex, and commute daily with bus, you need to be on the F-bus.

Also, if you are a party person, there's a week-end night bus that goes approximately the route of the F.

If you live in St genis/Thoiry, you should probably base yourself on a P+R, at Cern. But I don't know how it works, if you can get places, and also there's quite a lot of queues around there in the rush hour.

Biking from St Genis to the tram is a good solution.

tawb, May 12, 2015 @ 21:07