I don't go that way myself, but know of people who overnight within the port area, and others who book ahead ( but ask if an 8pm arrival time is OK) at Camping Kindervreugde at Adinkerke - just over the Belgian border.
Theres loads of places as you come out of port where trucks park but if you don’t fancy parking among them your best bet would be to make your way the the Auchan car park. Plenty park there & you can get some food in the morning & diesel anytime if you want.
Easiest way to get there is to go from port to A16 motorway. Turn left towards Belguim & take next exit into Dunc see signs Centre Commercial & Auchan is next roundabout turn left. Take you less than 10mins from port to there.
I believe some folk, park up at the Commercial Centre were Auchan supermarket is, we were at the "Buffalo Grill" there last Saturday, which could be handy if you are there in good time.
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