Be aware whatever you do that most portables do not have a neutral to ground bond for safety like the onboard has and shore power has. I don't know why they don't as pretty much all codes say that you must have, and only one, bond and it has to be at the power source. In an RV it means that shore power post is bonded, the onboard generator is bonded when connected and generating only, and an inverter has an auto bond when it is outputting AC power and must unbond when it is not if it also has an automatic transfer switch to it internally.Anybody who has a onboard genset not in use, had any issues just running off a Honda or other portable one?
I am not following what you are asking. Do you want to use the Honda and shore power at the same time?But you will still get the 120 volt power from say the Honda or other using the standard shore power plug?