If you mean you're thinking about leaving it cooking in the pot all week, don't do that. Just cook it according to the published recipes for crock pot pork roast. Break it down into meal size lots and refrigerate and heat one each night. What you want to avoid in such situations is repeatedly letting it spend time lukewarm. So break it down into meals.
Now, as to your safety/spoilage question. It won't be dangerous to leave it at normal cooking temperatures for a week, but it will suffer in texture, and any vegetables will turn to mush.
If you just meant to ask how long you could keep it after you cooked it, it will be okay refrigerated for a week, but again, break it down into meals, so it doesn't accumulate too much time at bacteria breeding temperatures.
"Kitchen duty is awarded only to those of manifest excellence..." - The Master, Dogen