Kanbula (卡布拉, if you are using Baidu maps, or 坎布拉 if you are using other English maps) is a small town 7 km from the east entrance of Kanbula National Park.
You can take a bus here from Xining and then get a taxi (or walk 7 km) to the entrance of Kanbula National Park. It is easy to get stranded here as it is unclear when the buses return to Xining. The bus schedule may vary but there was a bus that returned to Xining at 07:00 from the main street across from one of the nicer hotels. There is really only one street, so you should see the bus; be waiting at 06:30 to load. ~¥25 (2017)
Taxis will offer to take you back to Xining for a standard rate of ¥300. (2017)
There may be an option to take a taxi ~¥20 to the next nearest town where buses are more regular. (2017)
There are taxis that gather near the bus station.
Not much to see in town but the landscape is beautiful and the yellow river is near by. Kanbula National Park is 7 km away.
Walk around town.
Hike, boat, fish, and camp at the reservoir. There are no official camp grounds but people set up tents around the banks, usually to fish. Not sure on the whole legality thing of camping in China as a foreigner but some people have camped and boated on the reservoir with no problems. If it gets more popular there may be more restrictions. The only hard part is finding a beach without trash. You should be able to access the reservoir by continuing on the dirt road past the entrance to the national park from the east side or float down the river from upstream (west) side from Guide (experience on rivers is recommended).
There are plenty of stores if you need any supplies.
There are many restaurants serving many of the Qinghai staples.
Most restaurants and shops are Muslim so beer can be hard to find, but it is there.
There are several hotels around the bus drop off in case you get stranded or just want to spend the night somewhere out of the big city. ¥140 (2017) for a pretty nice double room. Next to the bus stop.
Kanbula National Park (you may be able to get to Guide on the other side of the park). Back to Xining 2½ hours ~¥25. You should be able to get to Xunhua also if you ask around.