Wire it the same as you would your house or garage and all in series. 12 or 14 ga Romex, switches, outlets and all. They make 12v bulbs the same as a “typical” light bulb size. By wireing it this way you can then just switch the bulbs when you do get a generator.
Make a cord with aligator clips and a male end then you can plug into the outlet/receptical mentioned below to run 12v.
Install an outlet on the outside of the house then you can make a double male end electrical cord and plug the generator into the house (wireing) from an extension cord. There are special connectors that eliminate the double male and then use any extension cord but they are rare, hardware store in Isle, MN carries them.
-Best Luck, Mark