You might have a way this trip if your father- in- law's rig has a better converter than yours has. You can yank out your batts and take them over to his rig and put them on the ground close enough, and hook them in parallel with his batts using your jumper cables, while he plugs into the Honda.
If you need 12v in your rig meantime, jumper to your truck or use 7-pin.
One problem with gen charging and a charger is-- How do you know when it is ok to shut off the generator? A good rule that forum member smk uses, is watch till battery voltage reaches 14.4v and then let things run for another hour, then shut down.
If you look at the graphs I posted earlier, you can see how that would work out fairly well.
