2003 durango rear disk brake swap?

Hi guys. I have a 2000 durango with rear drum brakes and I wanted to know what would be the process of swapping the brakes from a 2003 with rear disk brakes. I have 15" wheels with mud tires that I rather not change so my first question is if that would be an issue? The reason I want the better brakes is cause right now I feel like my rear brakes do not do anything. When I back my boat into the water I feel like I have to slam on the brake or it will end up in the water. I want a more even braking system. Let me know if any of you guys have done this swap and what is involved.