side trip from Hangzhou to Huangshan

Thanks for your quick reply to my questions, Sara.If we stayed two nights at Huangshan, is it better to stay one night for the first night at the foothills to explore tunxi, and second night up on Huanghan itself, since we will only reach Huangshan earliest after 10am from Hangzhou?Or do we need two full days to fully appreciate the scenic sites up on the hill ?How much is the bus fare from Hangzhou to Huangshan?Do we need to prebook the bus or can we just buy the tickets at the bus station in Hangzhou?Do we need to apply for any passes to go up Huangshan or to visit any of the tourist sites up on the hill?
Thanks again ,Sara. I feel more at ease now with your suggestions for our trip.