In a slow cooker, add the roast and all of the juices from the bag. Add the carrots and onions over the roast then pour the french onion soup and cream of mushroom soup over everything. Cover and cook on low for 4 hours or on high for 2 hours, or until vegetables have softened and roast is shredding.
In a large skillet on medium high heat add the butter, onion, and peppers; sauté until the onions and peppers have softened as well as started to brown. Remove from the skillet and set aside. In the same skillet add the mushrooms and sauté until they also have softened and developed color and add to the cooked onions and green pepper.
In a slow cooker add the roast, onions and potatoes. In a medium bowl, combine the remaining ingredients and pour over the roast, onions and potatoes. Cover and cook on high 4 to 6 hours or low for 8 to 10 hours.
