Hi,
I have found several slow cooker recipes for pork roast and sweet potatoes. You can always add mushrooms. The green beans will not need as much cooking, so you can add them toward the end. Enjoy!
http://www.bettycrocker.com/recipes/slow-cooker-garlic-pork-roast-and-sweet-potatoes/fb3db917-2982-476a-8e87-b9345bf98102
http://www.bettycrocker.com/recipes/slow-cooker-winter-pork-roast-dinner/0fe20d57-6c82-41c6-90c3-4e2ff3429a1f