Sounds to me like a good job for some simple custom aluminum or sheet metal baffle(s). use some careful observation of your RV underside's structure and where your RV floor is hot (my gasser floor gets REAL HOT immediately after the doghouse. Very successful radiant heat remediation is on-going with some stick-on coating, but I digress) and visually map how the air is mixing from the engine and over to the gen's fresh air flow.
A few dollars for metal and some carefully placed fasteners, and you should be able to change the air-flow route enough to overcome the problem. You also have the flexibilty of routing hot air away and/or cool air toward the gen. Small, even straight baffle(s)can make a big difference.
That is my next step to reduce my excess cabin heat. It was a problem, now just a minor annoyance.
I am sure we will both succeed brilliantly!