We went to Eurodisney a few weeks ago and also drove. Went with 2 cars, 3 satnavs (My Navman, and my friend's Tom Tom plus his built-in Mercedes one), and a pair of walkie talkies. Great fun.

The driving was tremendous fun with the walkies, ganging up on the french drivers by speaking to each other and holding up the fast lane so that we can pull in front of each other.

(Mobile phones ain't legal while driving but walkie talkies are.

Go figure.

).
With the satnavs it was so simple to get there and to even avoid the inevitable traffic jams when we left on the Sunday. They also helped us not miss the ferry thanks to their ETA features. (In fact we caught an earlier return one than was planned because we put our foot down on the way home.
Oh, and Disney was fun too.

But I'll save that for another thread.