My advice? If you're using a portable genny, use extension cords, and portable lights too. Don't even try to tie it in. If you want a stand-by genny, get a real one, and install it properly.
Agreed. For the generator at home, the extension cords live in a box all marked with where they run to (fridge 1, fridge 2, freezer and lights).
The lights are also in the box (2x 240VAC trouble lights with rough service 250-260V globes fitted). The generator has four outlets fitted for the four main leads with a double adaptor on the end of the lighting lead.
Piece of pie when needed, no hunting around for leads when you need them.