The public transportation in Oroville is not amazing, but strides have been made in recent years to have a more reliable system. The B-Line (http://www.blinetransit.com/) covers not only the core of the town, but also has hourly connections to neighboring towns.
Bicycling can be a wonderful way to see the area, especially in the Fall or Spring when the temperatures are more moderate and the natural scenery pleasing.
Taxis are scarce and not to be seen running around. You actually have to call a taxi to come to your specific location if you want one and they are not cheap.
While the immediate downtown area is a pleasant walk, to go anywhere else will require your own car. If you don't have one upon arrival, there are several rental offices in town such as Enterprise and Hertz.
