The problem that i can see is that insurance companies may require that the new roof,the electrical and plumbing issues, etc., be inspected by a company req before you can insure the place.
I was forced to sell my nice litle mobile home up in Rhinelander for a pittance when a insurance adjuster got up on the roof and decided the roof needed replacing NOW! I was given 30 days to replace the roof, a 4K-5K job for which I hadn't the money, or the ins co. would drop my HO ins. I also discovered that if you'v ever been dropped from owner's insurance, or let it lapse while living in the home,that too can make it very difficult for getting a new policy.
In my case, i knocked the 80 percent of the cost of a new roof; cost being determined by calling several roofing companies and averaging out the balance of their qoutoes. I also sold the home with full disclosure, including providing copies of the massive amount of plumbing work that had been done on the hosue since ipurchased it.
I had them sign off on a created document listing all the defects I had shown them, and then,at the bottom,they acknowledgedthe roof issue and that it had to be done ASAP,as in, I sold the house on Friday evening. They were to be starting on tearing off the roof on Saturday AM, and replacing it with a metal roof. They also quite willing stated that they waived their rights to a private inspection, and held the seller harmless if any issues were to arise after date of sale.
You CAN do this one your own, including hiring an inspector, but it;s best to have a lawyer specializing in real estate code transactions. It also wouldn't be a bad idea to talk to a good title firm just to make sure property lines are correct, and there are no leins or other encumbrances upon the property