I'm not a fan of ferries, so Folkestone/Calais on the train, sometimes it can be as cheap as the ferry, head towards Hamburg and take the E45 north to Denmark turn right at Kolding and follow the E20 you go across 2 amazing bridges and arrive in Sweden at Malmo with no seasickness ;D.
If you do want to cut out the drive through Denmark the best/cheapest/quickest is Travemunde/Trelleburg on TTlines, Calais to Travemunde is an easy day drive so if you get the night ferry you could do the whole trip in 3 days easily.
If you do want to cut out the drive through Denmark the best/cheapest/quickest is Travemunde/Trelleburg on TTlines, Calais to Travemunde is an easy day drive so if you get the night ferry you could do the whole trip in 3 days easily.