Your going to want it to go dormant,, the colder the better and the longer the cold the better, we always stopped irragation in the winters in the orchards, your going to want a cool temp over some time ,,, good time to do the prunning to help fruit set next year/season

A prunning tutorial for peaches I just did on the forum,, all stone fruits will follow the same prunning guidelines

Here is a link that might be useful: Peach Prunning

You didn't anser the question " At what temp should I protect it ? ".

It doesn't need any protection, a Gold Kist will only have damage if you maintain temps in the in the low 10's over a 30 day period. Like I said before;

"the colder the better and the longer the cold the better"