Harbin..what can I say,
First try the river swimming/dip. You don't know anyone but first break the ice and then literally break the ice and in you go!
Only 11 hours by fast train from Beijing, full of Russian architecture, visit the pedestrianised Zhongyang Dajie, (Central St)for a site of the flood monument dedicated to those who lost their lives in the 1998 and 1950's floods, see the river, (Song Hua He) at the top end of the street in winter and go skating, or in summer for a row and a swim...
10minutes and 1 or 2 yuan from the main station on bus 103 after getting off at the Russian built Cathedral of St. Sophia. Once you've seen the square and inside to a short history (in Chinese) of the city go to the front of the cathedral and cross the road, turn right walk down the road and turn left at the corner, beside Govt. Square and keep going straight crossing the roads till you hit a cobbled road. Left takes you to the Holiday Inn, right takes you to the river! Enjoy
p.s. the bus stop is across the road to the left as you leave the station.
Return buses leave from near the flood monument to your right if you face the river opposite the ubiquitous American fast food emporium.