I would *strongly* recommend finding a mechanic you feel you can trust. Let him go through what you have and do the work. The alternative *is* for you to learn how to use various gizmos (like voltmeters) and dig very deep into your MH. There are a number of systems and they all have issues. They also all have (likely) been upgraded / modified / repaired multiple times since they came from the factory. Finding out about the issues on the part installed at the factory is fun, but not of much use if it was swapped out for something completely different 2 years later.
Rebuilding this stuff can be fun, and you can save some money. The flip side is that you have to dig in and learn a bunch of stuff. You also have to buy a bunch of tools. In my experience, what you save on the parts, you spend on the tools
If you can haul all the tools and spare parts along, you can save some money on the road. That only happens after the first rebuild where you learn everything ...