Has anyone considered going to an EFI generator on their toy hauler instead of the carb unit?? I have discussed getting an EFI one when looking at ordering a new hauler. Dealer said not a problem.
One other thought. I'm not sure if your dealer has a plan for a return line but there is a way that's a lot easier than drilling the tank which would involve dropping it, draining it, drilling it, and then cleaning out (hopefully) all the metal shavings from drilling. Purchase this kit and install it in the tanks rubber fill neck. This will turn a few hour job into a matter of minutes job...