TQ60 offers great advice on locating someone qualified to help you. You also might try an automotive restoration shop to help locate a competent mechanic. These shops are usually staffed by the older mechanics.
My fear for you is that the RV sat a lot and was not maintained. This means dried-up seals, corrosion and rust. Moisture will kill the brake system, leaks will plague anything lubricated or pressurized. The previous owner may have know about internal issued and failed to tell you.
I would be very hesitant to throw money at this rig. You may have gotten a deal on it when purchased, but this could be just an expensive life experience. (We have all had at least one expensive lesson, some of us have had quite a few).
Since you are willing to learn, I would suggest pulling one of the valve covers. Looking at the condition of the internals might give you a clue. If you are able, remove the distributor cap. Then place a socket and breaker bar on the crankshaft damper nut. Rotate the nut one direction and then rotate it the other way. Watch how far you have to change direction on the nut before the distributor rotor changes direction. This will tell you how much slop is on the timing chain.
Buy a compression gauge at your local auto parts store. They are cheap. Take good readings of all of the cylinders. If you have low pressure on all of the cylinders (Under 120), or if you have one or two that are more than 15% lower than the others, you will have internal problems that will need to be addressed.
It is not that difficult to replace wiring. It is, however, very time consuming. Make sure that you solder all connections. Do not rely on crimp connections. Use the same gauge wire for each splice. Go one wire at a time to avoid mistakes.
With regards to the solenoid, find a direct replacement for the original.
With regards to your original comment about a backfire, carburetors do not usually cause a backfire on their own, unless extremely lean. A backfire is usually a timing issue, usually too far advanced. A slack timing chain can also cause this. I don't think that your distributor has conventional points, correct? If it does have points, any mis-adjustment will cause the timing to be off. (One degree of dwell error causes two degrees of timing error)
I would try to find help before throwing money at this.