Thanks for the quick replies. I have found the converter box and a good location for power plug. I guess I'M trying to figure out how this can be done and have the option of using either plug safely. I thought maybe of using a junction box to connect the two plugs then realized both of the power plugs would be hot which would be a safety issue
Your could just use a marine type switch.
These are rotary type switches that allow you to be hooked up to either shore power or a genset, but not both.
They are a "break before make" type switch. And they are not inexpensive, but probably cheaper then a 50 amp extension cord.
Many years ago I was in a BoatUS store, and in the discount rack was an odd looking cord, big and fat. Saw that it was a 50 amp 125-250 cord. We call the 50 amp cords either little 50 or big 50 (125 or 250 volts).
Had no use for it but figured for the discount price of $34 why not.....
Still have it, never used it and now it will go in the new trailer for an extension cord.