We've driven to Switzerland in either December, January or February about 7 or 8 times now. Even up the mountain at the end, we've never had to use chains. Before kids, we never bothered with them, now we do have them as a just in case.
PIL live there for several months a year and say it's very rare to actually need them. The Swiss are very good at keeping their roads clear. Read up on how to drive in cold or icy conditions and take note. We do have a get out though, if the conditions got bad, we could park the car at the bottom of the mountain and get the train up.
We tend to drive to Folkstone the night before, stay in a guest house then get on the 6.20am Eurotunnel. Then it's about 10 hours drive at the others side which we split. We don't really stop except for fuel and toilets. Eat in the car just to get there.
PIL like to cross the channel and overnight near Calais. Other times we have stopped in various places in France. We have friends who don't stop, they leave straight from school on the Friday, late night channel tunnel then drive through the night. Arrive at lunchtime and can ski on the Saturday afternoon. I don't think we'd cope with the night driving though.
We also got a sanef tag that blips at tolls as you drive through at 30 so you don't have to stop.
We also have to pay for parking at destination so take that off if you don't!
There are 5 of us so it's way cheaper than flying.
Flights for 5 = £2000-2500 plus £120 train fare to destination.
Driving for 5 = £800
Overnight in Folkstone £100
Channel tunnel £ 170 (Tesco vouchers!)
French motorway tolls £110
Swiss motor tax £32
Fuel £300
Parking £75
We drive about 1300 miles round trip. A 10 yr old petrol 7 seater with 330 miles to a tank so you could probably reduce the fuel costs if your car is smaller or more fuel efficient, or you do less distance.