Where could we start our visit if we will arrive at Hangzhou East?

I’m not sure about the touristic bus station you mentioned. However, if you are going to spend a full day in the city, the West Lake should be the best choice. From the East Railway Station, you can take the subway line 2 to Longxiangqiao. Take the Exit C4 and walk west about 250 yards, you will reach the shore of the lake. You can take a relaxing stroll to cover some sections of the lake view, or you can rent a bike to tour around.