I am going to buy a pork butt around 4 or 5 pounds. I need to cook it fast in like 2 or 3 hours.?

I need to cook this pork butt for pulled pork sandwiches in about 2 or 3 hours. How do I cook it? I have a crock pot and an oven and thats it. How long do I cook it for? and what vegetable am I supposed to put in the bottom?