Try this if you haven't already.
the 120v breakers OFF including the ones IN
Now try to start the generator, this will answer a few questions.
Turn the generator off, LEAVE the breakers off
Check the campground breakers. Reset if tripped.
Inside at your breaker panel flip ONE
of the 50amp breakers on, if it holds start turning on the breakers on THAT side of the panel, if they hold check to make sure some of your 120v things work.
If the main breaker doesn't hold make sure all breakers are OFF, recheck campground.
If the main breaker holds
turn the other main breaker on.
If it holds turn the breakers on that side on.
Hope this helps/works if not then back to wiring around the ATS mentioned by taylorbob1.
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