Hello

I am in Shanghai and I would like to travel during the Holidays.
2 options: Going to Kunming and travel in this area, or going to Beiging, stay there for round 3 days and go to Inner Mongolia.
I guess train is cheaper than plane, and I know that the trip to Kunming is quiet long, so I was wondering if I could make it in 2 times (taking 2 night trains).
What would be the prices for each option? To go to Kunming, in which town can I stop?
Thanks a lot