After 3 days in Tunis and nearby Carthage, including a half-day at the Bardo Museum and half-a-day in Tunis' old city, take a 2-day excursion to the historic old city of Kairouan.
One Week
After 3 days in Tunis and Carthage, head to one of the archaeological sites where the Bardo Museum's masterpieces were found - Sbeitla (Sufeitula) or Dougga are good options, for 2 days.Then head south to the Sahara for 3 days.
Two Weeks
Add on to the above itinerary, a 3-day Sahara trek from Douz. Next, head east to the island of Jerba for 2 mellow days on the beach. End your visit in the northwestern port of Tabarka, Tunisia's scuba diving capital.