Dennis,
I would not want to run a Honda in a rig without the generator prep.
I ran my set up for over two years and did not have a problem with the fumes. As I stated I did have the generator prep option and ran the generator only with the bay door open. With that option the bay was sealed from the basement compartment.
I would think under windy conditions any engine running could possibly cause fumes to enter the RV, this would even include a factory built in generator placed in the generator bay with the exhaust exiting out the bottom of the bay or the side of the rig. This happened with a class A motorhome we owned.
In Quartsite this past winter some ran their generators chained to the front jacks which were probably less than a couple of feet below where mine was located. With the 2955RL we had if I chained the generator to the rear of the rig, the generator would have been near my back door.
Here is a link to the set up I had.
Honda 2000i