I'd still call somewhere on the continent an 'N hour drive.' The 'drive' part indicates traveling by car the entire distance (I've never been on a eurotunnel tr

I'd still call somewhere on the continent an 'N hour drive.' The 'drive' part indicates traveling by car the entire distance (I've never been on a eurotunnel trip where we bothered getting a cabin so we were sat in the car the entire time) and in any case it's pretty clear what you meant given the absence of pure land routes.