Ferry crossing are between 1-1.5 hours with check-in of 45-60 mins. Most have special offers e.g.: £29-£49 for a car and up to x5 people each way.
www.dfdsseaways.co.uk (Norfolkline are now part of DFDS Seaways)
is very fast and they have reduced their prices:
Prices are from £42 for a car and up to x5 people each way. Also, they are not effected by bad weather.
You can also use TESCO vouchers for their clubcard deals - but you need to do this in advance.
By Car – It takes about 10 hours driving time from Calais and during the ski season it is a legal requirement to have snow chains (we recommend you do too!).
Michelin map of the area: here
Driving directions from: ViaMichelin