How long long does it take from kunming to the stone forest? Is two hours sufficient time to spend?

You can go to local East Bus Station to take bus to reach that attraction directly and takes about two hours on the way.
If you only visit the large and the small stone forests, two hours are enough. If you want to go to Naigu Stone forest, you need another an hour and a half.

Thank you for your prompt reply. Is was really a great help for my planning. Thank you once again.
Regards
TM Lau