Took the metro to the last stop on line 3 which is the Western Hills Park stop. I just followed the big crowd through the park. Most of the walking is on the main road in park. It is only open to the big shuttle buses which came along frequently.
The hike which is more of a walk is about 10 kms each way. I walked to the end and then opted to take the shuttle bus back to the subway station. There are several temples along the way and the main one is the Dragon's Gate temple on the far end. It costs 30 CNY to enter the final stretch that goes to the Dragon's Gate and more if you use the electric shuttle. The best views of Kunming and the lake are from that temple.