How can I go to North Bus Station from Kunming Railway Station?

Well, u can take subway line 2 at the railway station to South Ring Road. Transfer to line 1 which can directly take you to the North Bus Station.

To the red land, you can easily take a bus from North Station to Dongchuan first. I have no idea of the exact schedules, but many schedules are available. Afterwards, transfer to another bus to reach directly.

Thank you.
In case, from North Bus Station I take taxi/bus to Airport. How much and how long by bus/taxi?

By taxi, the fare may be CNY 70-80 (about 40 minutes).
Or, you may take bus line c136 from North Bus Station to East Bus Station for CNY 2. Then, change to subway line 6 to the airport for CNY 5. The whole trip taks about 1 hour.