Sounds like it is a doable project. However if you are not planning on keeping the boat for some time you will not get out of it the money spent to bring it back to top shape. Plan on spending a lot more time and more money than you expect on the project,
That being said a project like this can give you an object that you are proud to have completed. I have friends that enjoy rebuilding every thing from motorcycles, classic cars, farm tractors, and airplanes. Consider it as just another expensive hobby
Factory wiring manuals for the drive and motor are readily available on the internet for sale or can be downloaded for free.
There are usually no wiring diagrams for specific boats. Once again the internet will give you standard color codes for boat wiring and basic generic boat wiring diagrams. Rewiring an older boat can be frustrating for someone without basic wiring and electrical skills but isn't all that much different than for an automobile.
If you decide to start this project keep us posted on the project.