Schedule (4 days)
1st Day: Fly to Lhasa by flight (SZ4401,06:50/0850), have a rest getting use to the climate, stay in a 2-star hotel.
2nd Day: Visit Potala Palace, Jokhang Temple, Barhkor Street in Lhasa city, stay in 2-star hotel.
3rd Day: Visit Drepung Monastery, Sera Monastery, Norbu Lingka, stay in 2-star hotel.
4th Day: Take a morning flight back to Chengdu (SZ4402,09:40), and end the trip at the chendu airport.

Schedule (6 days) 
1st Day: Fly to Lhasa by flight (SZ4401,06:50/0850), have a rest getting use to the climate, stay in a 2-star hotel.
2nd Day: Visit Potala Palace, Jokhang Temple, Barhkor Street in Lhasa city, stay in 2-star hotel.
3rd Day: Visit Drepung Monastery, Sera Monastery, Norbu Lingka, stay in 2-star hotel.
4th Day: Lhasa/ Gyantse/ Xhigatse tour. Visit Yamdod TsoLake, Palcho Monastery of Gyantse, stay in Gyantse hotel.
5th Day: From Xhigatse to Lhasa.Visit Tashilhunpo Monastery in Xhigatse, stay in Lhasa in 2-star hotel.
6th Day: Take a morning flight back to Chengdu (SZ4402,09:40), and end the trip at the chendu airport. 

Note:
The Permit is given by the Tibetan Tour Bureau to regulate the tounism in Tibet. There are many areas in Tibet that are not open to the foreigners, so you need, though only for tour, to apply for the permit. 

It takes at least 7 days from the day you apply it to its arrival in Chengdu. What are the necessary materials to get the Permit. Tourist should provide us the copy of your passport at the first page as well as your occupation for the permit application. You can send it by fax 0086-28-83181388 or e-mail:abatour@sohu.com 

You can not get the Permit individually but only by the help of the certain tour agency. From the rules of the Tibetan Tourism Bureau the foreigners should be accompanied by a local tour guide