Changbaishan along Yalu river

We would like to visit the mountain coming from Dandong by car along the Yalu river and then continue on to Yanbian. On google maps I see the road along Yalu river is going in and out of the DPRK. Is that a problem? Do we need special authorisations and visas?
What is the best place to enter the mountain? (I cannot find the north slope entrance on Google Maps).
Also where can I find some information about staying with a local Korean family there?
Thanks!