One of the pleasures of touring in Jordan is that all of the major attractions are within easy reach of one another, and convenient one-, two- or three-day trips can be arranged from the capital Amman.
Undoubtedly, the country's most important site is Petra, a 3.5-hour drive from Amman. If you have the time, the best way to see Petra is to rent a car and spend a full day driving there via the Kings' Highway, stopping for lunch at the resthouse next to the Crusader castle at Kerak. Spend the second day visiting Petra, starting early in the morning, and drive to Aqaba in the late afternoon, returning to Amman the afternoon of the third day and driving through Wadi Rum on the way back. If you have a fourth day, spend the morning visiting the Amman Roman Theatre, the Citadel Hill Roman and Islamic monuments and the archaeological museum, then drive the 45 minutes to Jerash for a lunch there, an afternoon stroll through the ruins of the Roman city and see an early evening performance of the light and sound show, returning to Amman in time for dinner.
If you have only two days in Jordan, spend one day visiting Petra with the guided bus tours that operate dailly and on the second day see the Amman-Jerash area. Ideally, you should spend a week at least, allowing three days for the Kings' Highway, Pstra, Aqaba and Wadi Rum, one day for the Amman area, one day for Jerash and the Byzantine city of Umm al Jimal in the north, one day to see the oasis of Azraq and the Umayyad desert castles east of Amman, and a seventh day to meander through the Jordan Valley and take a swim in the buoyant, salty waters of the Dead Sea, at the lowest spot on earth.