If arriving in Pinglin on Highway 9 from Xindian. On the far side of town is highway 北42
(bei3/north 42). The road continues all the way to Taipei entering Muzha, but this is very much a secondary highway. The road is narrow, barely wide enough for two cars to pass and no center line or shoulders. Many of the sharp switchback turns have wide angle mirrors but many do not. It would be a nice country drive if you didn't have to worry about a car around every blind corner.
There are several campsites available near the 4, 13, and 15 km markers of 北42. At the 4 km marker there are two campsites. At the 13 km marker there is one campsite and the road to 黑龍潭 hēi lóng tán . At the 15 km marker there is one site.
Of the two sites at the 4 km marker, the first has nicer bathroom facilities. The second has nicer riverside campsites, but the toilet and bathing facilites are more rugged. The bathrooms do have hot water showers, but they were a bit dark and dirty. They also have a teahouse with KTV so you may not get to enjoy the peace and quiet of nature in the countryside.
At the 13 km marker, there is a small riverside site. There is a lack of shade here but the sites are directly on the riverside. I did not stay here, so don't know about toilet facilities but it looks like they could be questionable.
At the 15 km marker campsite the toilet facilities consist of two toilets and one shower for the whole campsite which is fine if it is not crowded. A shower is an additional $30.
All of these sites have a small shop selling basic supplies such as charcoal, grills, bottled water, and Taiwan Beer. If you need any specialty items be sure to stock up in town.