Well lots of bickering over CO but no one addressed the 100# gorilla. That would be the weight issue hanging off the back of the trailer.
First, you would need substantial frame work done to prevent failure. You don't want to be "that guy" who leaves his bumper and goodies on the side of the road and not know it until he stopped and walked around the back.
Consider how much weight will be added to beef up the frame attachments and bumper, plus the weight of the generator and whatever is used to secure it to the bumper. That is weight that you MUST compensate for up front or you will have sway issues.
Why do I say this? I considered it myself, posted a thread on it and was pretty much told what I just said.
If its an RV and not a trailer, different story, but on any trailer, those bumpers are not held on with much more than glue and bandaids. Once I got under mine and looked, the fabrication needed and what would have to be removed to get to the frame since it has an insulated belly, made it cost prohibitive. It would have also added 250 pounds to the tail.
There are plates you can bolt to the frame that hook under the square bumper that I was thinking to use, but I would then need to grind off the jack stands and cut the frame to make them work, and since the frame is thin steel, I wouldn't feel comfortable cutting it, so welding would be required.
In my case, I have the same Champion Genny, but without remote start, and plan to mount it above the LP tanks instead. I have been carrying it in the bed of the truck, and since it's only 85 pounds, it is really easy to move around.