Hello
What would be the best way to get from paris to dover?
Eurostar to Ashford, then local train to Dover Priory.
Seconded, Eurostar to Ashford and double back by train.
Do not consider a ferry, much slower and a lot less comfortable.
Only 4 trains per day stop at Ashford. Current timetable is here: http://www.eurostar.com/sites/default/files/pdf/timetable/6551%20UK%20Issue%2077.1.pdf
Two trains per hour Ashford to Dover, that sections is no problem.