Swapping Onan 5500 to Yamaha EF3000iSEB and solar help

I have been researching this but have conflicting advice, one says no worries, the other says will not work. We are preparing for full time RVing and want to be off the grid as much as possible.

-2012 Voltage 3905, 43ft, 50 amp.
-4 good batteries already installed
-Modified to carry small car in garage so much weight taken out.
-Dual AC but only use the main one, 15000 BTU.
-We do not use the Microwave/convection, removing unit.
-Onan 5500 is to loud and uses to much fuel and is heavy.
-Yamaha is lighter, less fuel, electric start, will fit in Onan location with fuel and exhaust done correctly.
-With good solar system we would hardly run the generator, just when gets to hot.

ISSUE:
50 amp uses dual 110 inputs, can I use a single output Yamaha or will there be extensive rewiring required, etc?

If the wiring is to crazy, like a whole new power panel, transfer switch, I might not want to do this

But if I can jumper them to act like single input units and change the outside plug to 30 amp only......I can do that if needed.

I did install a hard wired 50 amp surge supressor, I could remove it and install a 30 amp one if required as well.

Onan has 100 hours on it, any idea of what it should sell for?

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I was an electrician then spent 20 years in electronics in the USN so I can wire anything, I just need some help on what the real issues are.

Thanks, have a great day:)
Rick
ram@raamaudio.com
801-452-5858