As per above, you'll have a long journey to the South East Coast, then the crossing and then wherever you want to drive to. If it's for a weekend, it's going to be very tiring and you'll most likely not venture 'far' into Europe! If it's perhaps for 7-10 days or possibly longer, then it becomes more viable, but again depends on what you and the family are going to do there.
I've literally just 'hopped' into a car/van and driven across a few times now. I've not gone for holidaying, one time was to help my best mate move all his stuff back here from Amsterdam Holland and another time was a very very last minute trip to the Nurburgring Germany, both over 3 day weekends.
The Van journey was decent enough, just slower than I'd have liked as it was a Luton sized thing (16 foot box with a tail lift). I did give it some throttle to see what I could get out of it which was sort of fun! A weekend of packing and a bit of partying and it was time to drive the thing back, much slower of course, still took the best part of a day!
The Nurburgring trip was fantastic - went with a friend and his two mates in two 'very FAST' BMW's so it wasn't 'long' before pulling into Dover!! A quick Rail drive on/off crossing and it also wasn't 'long' before getting to the Nordschleife - excellent, exhilarating fun for 2 days and then a just as quick if not quicker return back to the UK (south east).
I was knackered on both visits!
Both visits were awesome!
As soon as I get the chance, I'm doing it again, Nurburgring is always a standard choice but may well also do Le Mans or Spa as well - these two venues are if you are into track/fast cars/automotive/driving fun !
Cheers! DtM! West London & Slough UK!