What the city is best for
Bursa should be planned by area, travel time and what you actually want to do. It works especially well for culture, food, history, nature and mountains. The main anchors are Ulu Cami, Koza Han, Green Mosque, Tombs of Osman and Orhan, Uludağ and thermal baths, but the value of the trip depends heavily on where you stay and how you structure the days.
The most useful bases are City centre for mosques and bazaars, Çekirge for thermal hotels, Mudanya for coastal feel and Uludağ for mountain stays. Choose short access to what you will do most, not just the lowest hotel price. For short stays, a better location often saves both time and transport.