as of last august 2006, the southern friendship hiway from yamdrok-tso to gyangze was closed. the classic itinerary from lhasa to gyangze to shigatse and back to lhasa had to be negotiated differently - vehicles had to go from lhasa west to shigatse via the northern friendship hiway then from shigatse southeast to gyangze via the southern friendship hiway (that portion was open).
to get back to lhasa, the above route would just be taken in reverse. to avoid backtracking all the way to shigatse, there apparently is a shortcut.
from gyangze, just after a few minutes drive on the southern friendship hiway heading northwest to shigatse, there is a dirt road on the right that heads north eventually hitting the northern friendship hiway. i'm not too sure if this road is what appears on the lonely planet guidebook to tibet (page 163, map of tsang) as the one that passes through rinphug (renbu) or not.
either way, it's not much of a road, more like a trail that gets obscured if the ground is wet. very easy to get stuck or lost. your mobile phones will not work there as it's in between the mountains so you won't be able to call for help. my driver, as experienced as he was, stopped several times to verify if we were going the right way. I DEFINITELY DON'T RECOMMEND TAKING IT JUST TO SAVE A FEW HOURS' DRIVING TIME.
Around the monastery there are a lot of dogs. These dogs are not the nice type that like to be cuddled, but they do bite!
So be aware of them and as long as you don't come too close there is no problem.
Walking through muddy streets can be more difficult than you think. Sometimes it looks like a stable piece but when you put you foot down you get sucked in. This happened to our tourleader, and we were happy it weren't our shoes and pants that needed a cleaning. Boy this was smelly....