Right.
Ferry advice (I worked on the Dover run as Chief Officer, so I know what I'm talking about here)
You're heading North when you get across the channel, so the best ferry to get will be DFDS on the Dover-Dunkerque route.
This lands you a good distance further north than landing at Calais.
Obviously night ferries are cheaper than day ferries. But you can often get good deals on DFDS website if you book in advance.
Is your Zed lowered? If so - be sure to check in as a "LOW VEHICLE". This is extremely important. Otherwise they will try and stick you up on Deck 5, which is a very bad ramp, and more than likely to take your front nose off at the bottom, and your exhaust off at the top.
With DFDS, you booking is for the ferry you are booked on. Although they allow you to travel on the crossing before and after yours without a surcharge.
When you arrive in Dover, come down along the M20, drive through the town all the way. Enter the docks, by going straight on at the last roundabout.
Follow the "car" symbol.
Go through French Passport Control
Follow road to the check-in booths, and aim for the DFDS ones.
They will give you a lane number. Drive round and into that lane.
Easy as that.
Any other ferry stuff, just yell out.