Calais is a city in the Nord-Pas de Calais region of France. It is the closest point on the French mainland to England; Dover lies across the English Channel (La Manche) just 32 km (20 miles) away. The town has a major cross-channel ferry port and the French entrance to the Channel Tunnel is nearby. Calais is popular with British day-trippers arriving by ferry or on Channel Tunnel shuttle trains one reason being due to the fact that France has lower taxes on alcohol and tobacco. Large warehouse supermarkets have sprung up on the outskirts of Calais just to serve these British "booze cruisers" who return to the UK with their suspensions groaning under the weight of cheap booze and cigarettes. While most tourists view the town as simply a port there is a little more to the town.
Calais ferry port is located across the Channel from Dover on the coast of Northern France. It is is the closest French town to the United Kingdom. The strait of Dover is one of the most frequented shipping lanes in the world. Calais ferry port is situated to allow easy access to the town itself but also to shops outside the town many of which are designed to sell alcohol to visitors from the UK where higher taxation means alcohol of all kinds is normally priced higher.
Free car parking facilities are available in front of the Calais ferry terminal and the maximum stay is of three days.
The port is also directly linked to the French motorway system. The A26/E15, which provides access to the heart of France including Paris and beyond and the A16/E40, which is a gateway to Benelux and the northern European motorway systems. The A16/E402 directs you to western France.
Ferry crossings from Dover to Calais take typically around one hour and fifteen minutes with it normally recommended that passengers arrive at least an hour prior to departure - however operators' advice may change. Two operators operate this route, P&O and Seafrance. P&O is an Enligsh operator while Seafrance is French owned. However, the port of Dover is not only connected to Calais. Another popular route is Dover to Dunkirk and this route is operated by Norfolkline ferries which has recently become part of DFDS Seaways.
Running from Folkestone to the western edge of Calais the service takes about 35 minutes (although only about 20 minutes are in the tunnel) and offers the fastest way to go between the countries; this service is for passengers with cars only who remain with their car for the duration of the short trip, onboard there are no restaurants (although there are facilities – a fast food restaurant and various shops in the terminal buildings) but there are toilets.
Running from London St Pancras, Ebbsfleet and Ashford, Eurostar offers Calais in 1 hour; there are around 3 trains a day in each direction. Note that the Calais Fréthun TGV stop is some distance from Calais itself; there are however shuttle buses and taxis.
Cars can be taken to the South of France, destinations such as Narbonne, Marseille and Lyon can be reached by train (your car is carried with you).
Most people travel by car around the town, but there is a comprehensive network of buses running from the town centre to the suburbs and Cité Europe. The port is served by a special shuttle bus - although via a footbridge the centre and the harbour terminal are only 15 mins apart. Bus #5 is useful for reaching the large Auchan and Carrefour hypermarkets and the Cite Europe shopping mall and #6 goes to Calais Frethun Eurostar station. Services run every 30 minutes during the day and cost between 80c and €1 (board through the front door and pay the driver) and all terminate outside the Gare D'Ville.
There is a fantastic crepe restaurant called La Chênaie in Rue Jean de Vienne.
For a lot more infos, have a look on the Couchsurfing Wiki Page of Calais  .
A lot as you can imagine ... too close to UK ! ;-)
Have a look on the Couchsurfing Wiki page of Calais  .
If unfortunately, you don't find a couch, here are 2 cheap but serious adresses :
To hitchhike to Belgium or the Netherlands, if you leave the terminal, you must walk 500m through a large car park, after which you will see roundabout and an on-ramp to the motorway. That is the place to hitch a ride: there is enough space even for a big lorry.
For a more 'traditional' experience of France, Saint Omer is a mere 26 miles (43 kilometres) down the road from Calais. The Saturday morning market on its main square, the Place Foch, can be enjoyable. There are also good affordable restaurants and friendly bars, as well as interesting architecture.