Dover likes to present itself as much more than just a port from which people depart and to which they arrive. The actual place is steeped in history and is really worth a visit for day as a stopover on your journey or even for longer.
Getting to Dover is easy, as all you have to do is get onto the M25 somewhere and look for the junction with the M20, which takes you all the way there, or the M2, which joins with the A2 to also take you to the port.
There are a wide range of tourist attractions around the town which cater for all ages. Dover Castle is well worth visiting, particularly due to the network of secret tunnels which are cut deep into the white cliffs. Visitors to the castle can experience what life used to be like there through the ages and can also join the interesting list of visitors, including Winston Churchill and Henry VIII. Should you have the energy you can climb to the top of the castle via the very steep staircase. This is quite an effort but you will be rewarded with a breathtaking view.
The white cliffs themselves were made famous by the Vera Lynn song "White Cliffs of Dover" which aimed to fill soldiers with pride during the second world war at what they were fighting for and where they would come back to.
On the waterfront is the Dover esplanade, which features in particular the Prince of Wales pier, which has the white cliffs as a dramatic backdrop. There are also a variety of museums which cover transport and also life in Dover starting with the ancient Celts and moving through to World War II and later. You can get bus tours and also the "White Cliffs Experience".
The main ferry routes from Dover are to Calais, Dunkirk and Ostende. Calais is the shortest route possible from the UK to Europe, and famously contains particularly cheap shopping facilities in its hypermarkets. This is why many people take their cars to Calais to stock up with (mainly) drink, a pilgrimage made most often before Christmas and New Year parties. Ostende is the main port in Brussels and you can use it to go to Brussels or Bruges. Dunkirk, of course, is where the UK and US armies landed on June 6th 1944, a day more famously known as "D-Day".
You can find further details on all of the attraction mentioned above at http://www.dover-web.co.uk or you could also go to the Tourist information Office in the town centre of Dover.