Thanks to everyone who replied to this thread. Your advice is much appreciated. If I decide to go the route of a truck camper I will go with a gas powered, rear wheel drive heavy duty truck.
Now that the decision has been made, I will tell you that the reason I wanted a Tundra is the terrific rating they get in terms of cost and frequency of repairs from the survey that Consumer Reports subscribers submit but I doubt if many of those people haul a truck camper or heavy cargo with their vehicles.