There is a well sign-posted walk around Ping'An that takes you through Ping'An town, and up to both viewpoints - Viewpoint 1 (called Nine Dragons and Five Tigers) and Viewpoint 2 (Seven Stars with Moon), both of which have spectacular views of the town and surrounding terraces. The route is well sign-posted (look for the stone-engraved maps about the place) with good paths; completing the full circuit takes about 1-1½ hrs. The hike is easier if you head through the village up to Viewpoint 2 then across the hills to Viewpoint 1 and back down steeply to Ping'An.
A short hike through Ping'An to the summit takes about 2 hours to complete, depending on fitness. JinKeng is slightly larger so may take more time. It is possible to hike between Ping'An and DaZhai (JinKeng) in about 3 hours, enquire about guides once at either of the villages. Longer hikes spanning more than one day are possible and will allow you to access more beautiful and less touristy areas of the mountain.