Well, I think I went into most of this already in my "stopping superintelligence" essay.

Stopping is one of the simplest possible desires - and you have a better chance of being able to program that in than practically anything else.

I gave several proposals to deal with the possible issues associated with stopping at an unknown point resulting in plans beyond that point still being executed by minions or sub-contractors - including scheduling shutdowns in advance, ensuring a period of quiescence before the shutdown - and not running for extended periods of time.