extend generator exhaust above roof
You also might to make sure the pipe clears the top of the rig. For example, my 25ft Class C fleetwood Jam has a vent just 3 feet from the rear, in the middle of the roof. Running my pipe strait up puts it right in line with the vent. If the wind is blowing.. you get the picture. Pluse, make sure your awning is out of the way. Again, a pipe on my unit wouldn't work as the awning extends behind where my gen is (rear of RV, passenger side). I can use 45deg bends but was told this isn't good on the gen for an extended period of time.