Chunnel is a far better option than the ferry, except when there is a fire in the tunnel, people queue-jump and you therefore miss your scheduled train, your kids need a piss 1 minute into the journey (the one loo on a chunnel train somehow predates medieval despite having been built in the 1980s) or you forget that you are a “high vehicle” when you have a roofbox on and hold up the whole train for 20 minutes.

Notwithstanding the above, and even though we live in West Wales, we go Drive / Chunnel / Drive all the way to the Alps.  It is a brutal 17 hour journey, but the benefits of infant silence (thanks to DVD/Headphones), lack of multiple deadlines, avoiding airports and having our own wheels in resort make up for the downsides.

In fact, I think my kids even look forward to the 17 hours they can spend watching Disney movies and eating kitkats (a rare treat in our anti-screen /anti-packaged food fascist household).

Having control over your travelling environment is the key.  Being subjected to the unfamiliar constraints of an airport / plane / train / coach is inherently stressful when you have kids, but the inside of your car is a familiar place where you can at least mitigate the risk of the children contracting pneumonia or being kidnapped.

The one loo on a chunnel train somehow predates medieval despite having been built in the 1980s.

For these reasons, my considered advice is for you to drive, take the chunnel, then drive on to the Alps if you have kids.

However, there are some alternatives that can be considered.

1. Walk / hitch hike:  Great adventure, higher likelihood to get an axe in your head, could be difficult to get back in time for the start of the new school term.
2. Google car:  Awesome.  Can’t wait.  Until my car runs over a Frenchman and I get sued by the EU / attacked by Gallic peasants with pitch-forks who don’t like technology / modern things.
3. Private jet / helicopter: Perfect, but you will have to act like a dick in every other aspect of your life in order for this to become a reality.
4. Teleportation: Works perfectly, until someone gets the settings wrong and you arrive at your destination with your wife’s head and your son’s penis is attached to your elbow.