I've done this six times, ex Brother in Law lived in Brussels for a few years and I also drove down to see The Monaco GP once. It's a long drive from here down to Dover or Folkestone so your best bet is to stay overnight around the Dover area, plenty of B&B's. I say this because you don't want to arrive in France in the dark if you've never driven on the right before and you'll be fresher and more relaxed. It's also a lot easier to find your way out of the docks by daylight . One thing you should keep in mind is that while French, Belgian and German roads are good the driving standards are diabolical. Remind me to tell you the story about The French Nuns someday
Coming back is another thing too, don't be tempted to save a bit of money by getting an overnight ferry, the only time I did this I had a few micro sleeps on the M1 at 80 mph, not good . Another thing is that once you get away from the coast of France then not a lot of English is spoken (that caused a few problems when my Mini broke down slap bang in the middle of France ). Not so bad in Germany and Belgium though where most people under the age of 25 speak good English.
BTW, The first time I drove on the Continent I had a Mini. Ignoring my above advice, we got straight on the ferry and arrived in Calais in the dark....did I mention the Storm Force 10 that was blowing in the channel? Couldn't even sail from Folkestone, everyone on the boat, even some of the crew, were sick as dogs, journey took twice as long, absolute nightmare for everyone...lucky that I never suffer from motion sickness . Then of course, we couldn't get the tent up in the howling gale, we had to find large lumps of concrete to keep it from flying away.
Pete