I guess a "real" system would be best but those plugs and sockets take up a lot of space. I don't know how small some of the chargers are either. I had a 18' boat
and that install would take an awful lot of what little space there was.
I would go like you said and pretend I was using a power tool or a vacuum cleaner for a while - or something. People do that extension cord thing all the time. Without the the GFI.