I haven't carried a generator yet. I have 2 Honda 2000's that I plan to just set on the truck rear floorboard when I travel. My A/C is 11,000BTU and just 1 of the Honda's doesn't run it well. It did once, but not another time. I wish I had the 9,000 BTU Coleman Cub.
You may want to look into a rear cargo carrier. I have one and my scissor steps will just clear the rear edge. If you have the new Bigfoot rear bumper plus steps, I'm not sure how a carrier would work. I would have to look closely at how to store the Honda outside to prevent theft.
Congrats on the Bigfoot! Excellent choice.