Hi - I've always steered clear of long haul driving but my dh thinks it could be a good idea this year - he want to buy a dvd player and go for it. All and any advice, yes's, no's and 'you're mad's' welcomed.
we've done it with 2 kids, from when they were 4 and 2. In-car DVD is vital, make sure you find headphones they all feel comfortable with. Perahaps with 3 kids you mayneed to look at getting 2 or at least one with 2 screens. We tend to find ours go into a stupour after about 1.5 hrs driving so we often push on and do 4 hr streches. However plan to stop every 2 or 3 hrs. Also make sure you do stop and make the journey part of the holiday.
Last summer we (actually dh was the one doing the driving) drove from devon to northern italy, admittedly just with two dc (then 4 and 2). We did it without a dvd and a stereo! Have to say that I read so many books and sang so many songs that by the time we got to Italy I had completely lost my voice. (therefore I forced dh to buy a stero for the journey back...). We drove for 3hrs stretches. Lots of snacks. We stopped a few times to see some castles. And luckily they also fell asleep... good luck!
I'd recommend it. We did it every year from DS being 3 to him becoming a teenager. His sister is 4 years older.
This was in the days before DVD players and such. I used to start stocking up on bits and bobs for a few weeks before hand, so I had a lovely bag of tricks to keep them amused. Colouring books, washable crayola felt tips (new sets of felt tips always a treat) puzzle books and tapes. Plus plenty of fruit and non-sugary/sticky drinks.
Stop every 2 to 3 hours. Stop were there are fields or somewhere to chase around and play tig or something.
Spread the drive over 2 days and stop overnight in Dijon. Once we made it all the way to Lyon in a day, but it was a hard slog.
We used to go to northern spain camping. God I miss those holidays!