Caen is a college city, very active. In summer, tourists (mainly British and German) gather in Normandy for WWII remains and the Memorial for peace. Caen is a modern city, 80% leveled in 1944 and rebuilt in the 50s and 60s. However, some old buildings remain, especially churches.
trains leave about every 2 hours from Paris Saint-Lazare station to Caen and Cherbourg. It lasts about 2 hours long, costs 29,10 € (full price). If you book early, you can get tickets as cheap as 15 €. Out of rush hours, tickets cost 22,40 € for people under 25 years-old.
Note that the train posting in Paris St-Lazare can be confusing to the first time traveler. The train line number ("la voie") is not posted unil 15-20 minutes before the departure, so do not panic if you arrive earlier than that (notice that the train will be at a line number near to the office "Grandes Lignes"). Look for the train heading to Cherbourg. Caen will not be the listed destination, as it is a stop along the way. Do not forget to punch ("composter") your ticket in one of the yellow machines before boarding. This will validate your ticket.
D-Day Landing Beaches. Caen is close enough to the D-Day sites to act as a base from which to explore the D-Day sites. It is a short train ride from Caen to Bayeux. From Bayeux train station, you can catch a bus to some of the D-Day beaches. On the bus website  there is a map of the bus route to the D-Day beaches. Bus No. 70 takes you to Omaha beach, the American cemetery, and to Pointe Du Hoc. Bus No. 74 takes you to Arromanches beach - the location of the Mulberry harbors. According to Wikipedia: "Omaha beach is 5 miles (8 km) long, from east of Sainte-Honorine-des-Pertes to west of Vierville-sur-Mer" and these villages are accessible via the No. 70 bus. Note very carefully from the bus timetable that buses are few and far between, hence, you would schedule your bus trip to take into account the few buses. Also, buses do not run when there is heavy snow, so check the bus website beforehand during snow season.
The Vaugueux is full of restaurants.
The Rue Ecuyère, near to the Rue Saint Pierre is famous for its bars. If you are looking for a pub, you will find some at the harbour located Quai Vendeuve.
The little 17-th century harbor of Honfleur (179 km north-east)