Directions from Geneva Airport if hiring a car:
If hiring from the French side of the airport:
The first problem is getting to your car! You enter Switzerland via passport control, collect your baggage, and come through into the arrivals hall (Swiss side), then turn left, and then left again up the escalator to the Departures level. (Geneva's luggage trolleys go up and down the escalators, which is fun!) Turn right at the top of the escalator, and go right along to the end of the arrivals hall, following signs for FRANCE. You then go through another passport control and back into French territory, where you will find the French check-in desks and car-hire counters.
If you hire a car from the French side of the airport, the car probably will not have a Swiss Vignette (to allow you to use Swiss motorways), so you need to go through the centre of Geneva - ask the car hire people for a map, and follow these directions:
You leave the hire car carpark along a fenced road/tunnel which is theoretically in "France", then when you hit the main road, turn hard RIGHT into the Douanes back into Switzerland and another tunnel. Follow signs for Geneve Centre and (more importantly) Lac until you hit the Lac; follow along the north side of the Lac and left over the first bridge. Get into the middle lane on this bridge, and bear left again on the south side, but get over to the right lane. Follow signs for Chamonix and Mont Blanc tunnel, NOT Evian (left lane).
Follow the main road out towards Chamonix (a long climb up through the suburbs), avoiding the odd tram track. Just after the road levels out, look out for the signs again, because you have to take a right at a rather inconspicuous junction (signposted Chamonix and France), and then after about 300m, left again. This then takes you down via the Swiss/French border to the Autoroute (A411 spur to A40), where you follow signs for Chamonix/Mont Blanc again. You'll need Euro 1.50 + Euro 1.60 for the Autoroute, if you want to use the automatic gates, but there are manned gates which will give change (and probably take credit cards too!).
Leave Autoroute at J18, SP Scionzier (and Morzine/Avoriaz/Les Gets), and follow signs for Morzine/Avoriaz/Les Gets through Cluses onto D902. Unless traffic is bad, it takes about 25 min from leaving A40 to Les Gets. Up and over one ridge, down again into Taninges; a couple of 3-lane bits of road where overtaking may be possible. Right and left in Taninges, SP Morzine/Avoriaz & Les Gets, and up the climb to Les Gets. Don't even think about overtaking after Taninges. You may need your chains after Cluses if there has been recent heavy snow.
Supermarket: If you want to visit the Carrefour hypermarket in Cluses (open to 8pm most nights, closed Sunday), turn right at the large roundabout after the bridge and several traffic lights. (Les Gets etc signed left at this roundabout, onto a by-pass). Carrefour is 500 m along this road, on R. On leaving Carrefour, turn R (ie continue along same road) and about 500m further, turn L (SP Taninges, Les Gets, etc). Follow to TL, straight across, and up to small roundabout where you rejoin the bypass route).
· Through centre of Geneva (Signs for LAC)
· Follow signs CHAMONIX/MONT BLANC
· Leave A40 at J18 (CLUSES/SCIONZIER) and follow signs LES GETS
· In Les Gets, follow signs LA TURCHE/LAC, then GROUPE SCOLAIRE/LAC.
If hiring from the Swiss side:
Either (a) head for the city centre, straight across the bridge, and follow the route as above, or:
(b) follow the Green signs for France via Autoroute (NOT Lausanne), which brings you to the border just before the A40, where you follow signs for Chamonix/Mont Blanc. Refer now to the directions from Calais - you are approaching the nasty junction referred to in those directions).
The all-motorway route from the airport is about 15km longer than via the city centre, and takes about the same time, depending on traffic.
Directions from Chalet Chardon to Geneva Airport (French Side):
Returning a French hire car to the French side of the airport is a little tricky, especially if you do not have a Vignette. Allow 2hrs to top up with fuel, return the car and get to the check-in.
From the chalet, go down Route du Lac, bear R at the rubbish hut towards the centre of Les Gets, until you get to the sloping-T junction (by Le Petit Alimentation), where you turn hard Left, SP Geneve/Taninges. Follow (1km) to main road, where you turn Left (by Chinfrey Hotel). Down to Taninges, R then L in Taninges, then up and over to Cluses. At the first roundabout in Cluses, turn R and follow all signs for A40 and Geneve.
From here on, do NOT follow any signs for Airport.
Leave the motorway at the junction for Geneve Vallard - going down a long hill, past a large Migros shopping centre on the right, get into the left hand lane, and go straight on while the main motorway turns hard right.
Through Douane, keep straight on until nearing centre of Geneva.
Look out for and follow signs for Parking Mont Blanc - at a 5-way set of traffic lights, go straight on for about 200m , then turn R, cross another couple of roads, then turn L, all SP "P Mont Blanc". (If lost, follow signs for Lac until you hit the Lac, then turn left).
Go past the entrance to P Mont Blanc, cross the bridge, turn Right on N side of Bridge, and hug the Lac for 500m or so. Follow road round to left, up the hill, SP Ferney Voltaire.
Follow road for a couple of km, SP Ferney Voltaire, France, etc. Once over the crest of the hill, there are two petrol stations - last before border (but diesel cheaper in France!).
Roundabout - keep following signs Ferney Voltaire and France. DON'T follow signs Airport. Turn Right, through a tunnel and through Douane.
If you still need diesel, carry on past Douane to a garage after 200m, then retrace your steps.
Assuming you have already filled up, then turn left immediately after Douane, up a small road (SP Aeroport, Secteur Francaise??). Follow this road, through tunnel, and follow signs for hire car return. Drive to far end of the hire car carpark, do a U-turn in the unloading bay at the end, then back into the car park and bear immediately right into the car park itself, beware high kerb!) and find a bay for the appropriate hire co. Up the elevator at the end of car park, return hire keys, then go through to the Swiss sector to check in. (Don't try to get them to open a desk to check you in on the French side - it takes longer than walking through).
Returning a car to the Swiss side:
Straightforward, just follow signs for airport; probably easiest/quickest on a Saturday just to go the long way round via the Autoroute.