I have a TransferFlo 50 gal in bed. I've had this tank for 17 years and it's more than paid for itself. When I changed it from the 02 to the 07 I had to buy a new brain to get the auto transfer to work.
I have a brother who was delivering RVs for awhile. With his truck I used an electric pump with a switch in the cab and a small flashing multi colored LED light that was on when the pump was on. He couldn't forget to turn the pump off. Plus I wired it so that it was switched power. I also installed a fuel gauge in the cab for him