The box connections are ONAN
Beyond that generator box stuff is Cummins. Working within the gen box the Onan manuals show clear diagrams for wire numbers. Cummins used less clear photocopies.
And yeah the older models were reconnectable.
I recommend manual over ride of
Fuel rail pump
GLOW PLUGS
And a 12 or 24 hour shutdown timer for convenience.
I know of no remote starter that is sensible if distance is so great starter and engine noise is not discernible. Changing a starter and ring gear is not easy or cheap.
A heavy duty pushbutton like a Cole Hersee is great for glow plugs. A pilot light drawn from the glow plug power wire is best. If you decide on a glow plug relay a Ford fender mount is far more reliable then an original equipment Essex
The most complicated circuit is the fuel solenoid engine run with temp and oil pressure shut down. It uses a latching relay for the fuel solenoid.
I've retrofitted many a MURPHY temp/pressure panel to replace the OEM Murphy gauges are bullet proof.
