There have been NO restrictions for crossing the North/South border in Cyprus since 2003 for EU citizens. You are free to cross and stay as long as you wish by only producing your passport or ID card. Here is a number of Cyprus border crossings that can be crossed with a vehicle, bicycle or by foot:

• Metehan (also called Agios Dometios or Kermiya) in the west of Nicosia
• Ledra Palace/Ledra Street and Locmaci in central Nicosia:  Just a walk to the other side of the city. 
• Dhekelia (also known as Beyarmudu, Pergamos or Pile)
• Akyar (also called Strovilia or Azios Nikolaos) in British Eastern Sovereign Base Area in Famagusta, right on the Larnaca-Famagusta road.
• Yesilirmak (also known as Limnitis) near Guzelyurt (Morphou).