Jeffery:
there are a lot of opinions out there, and the more you read the more you will get confused. We are in the same boat as you. WOW have I been doing a lot of reading. Bottom line. find a dealer with years of being in business that you can trust. He sees many more people that tow with all type vehicles. It is in their best interest to set you up wit the correct weight and camper for you. Of course you also have to do your homework. Get the literature from your truck dealer that pertains to your specific truck and find all the ratings INCLUDING the gears in your truck. you say you have an f150 5.4 rated at towing 9000 lbs. you fail to say crew cab or standard trans that will also make a difference in what you tow. remember there is no difference in the engine size ex. 5.4 is a 5.4 same as getting a diesel. f250 has a 6.0 f350 is still a 6.0 just a difference in the weight of your vehicle and the suspension, (springs, shocks ETC...)
enough ramblin on here... Good luck