Have you already booked? If you haven't, think about what priorities you have for the journey and week rather than going for the first good deal.
Driving time and route: shortest kms is not necessarily shortest in time, toll fees and any alternative routes to lower cost, road conditions on last leg up the mountain, whether you need winter tyres or not eg we drive in April to a resort where mountain paths are clear by that time so don't need to change tyres.
Resort amenities : whether you want swimming pool, ice rink cinema etc, supermarkets within walking or driving distance.
Ski amenities : distance to ski school, ski garderie, ski lifts, ski hire shop even.
Prices : discounts for family groups on ski school, ski passes, ski equipment.
Ski area suitability : enough ski area for good skiers or beginners areas easily accessible.
We've never been stuck in traffic, can't help you there. We do 850ish kms and start 7am in the morning, drive 5 or 6 hours with just toilet stops and changing drivers, then we stop somewhere nice for a long lunch break, usually for us it is Bern in Switzerland, then 2 or 3 hours further into the Chamonix valley. We try to arrive by 6pm and always check the ski hire shop opening times so we can collect the skis the night before.
We can't unfortunately bring more than a days food in our car as we have the smallest 7 seater with 6 seats filled and 1 seat space for 2 large holdalls (now an expert at packing into that space enough for 6 people). So we also know exactly where the supermarkets are in resort so we can shop quickly if it is a Saturday arrival, as most shops are closed on Sunday.
We are going back to the same village for the 3rd time. We LOVE les Houches because everything is so close, it is very cheap for a family of 6, our friends are just a short train ride away.
France is a great place to self cater as most French ski this way and there is a good choice of accommodation from a multitude of French companies - ok some are less French, having booked Pierre et Vacances, the bill is actually marked Center Parcs.