A "cheater plug" in along with a Honda EU 2000i ????

Rephrasing, to make sure I got this:

You have a 50 amp connector. On one leg, you will have the 30 amp shore power. On the other leg, you want to run a Honda generator? Or, do you want both the 30 amp power and the Honda generator on the same legs.

I don't know if this can be done safely, because either the Honda would get yanked into phase with shore power, the generator gets killed by the backfeed, or you get 240 volts where 120 is expected.