About the route: Arrive in Hangzhou airport and take the airport bus to the city center. Hangzhou Railway Station has many bullet trains to Shanghai (1.5 hours), you can leaving for Shanghai at next day afternoon. You can spend two nights in SHanghai then take bullet train from shanghai Railway station (half a hour) or buses to Suzhou (1.5 hours). Spend one day in Suzhou then go to Wuxi, by bus. Then take bullet train from Wuxi to Hangzhou within 3 hours. Hangzhou Railway Station has the direct shuttle bus to the airport.
It is a bit wet and cold in Jan. Need to weaer down coat. It is not very easy to buy ticket at that time. You can book onlin, but I never try this. You can also shuttle among those cities by bus. They are not far away from each other.