You will be close to double your payload. Slow death for the truck. Hallmark does make campers that would work. For the last year I have used a camper of similar wet weight on my Tundra. Works OK but as I will be driving back and forth to AK for the summers from now own I am going to a one ton truck in the next few months. I have air bags and e rated tires but no other suspension upgrades. You will need tie downs. I have torklift ones. I use an extension to hook up the electrical rather than installing another plug in the bed. And most likely you will need to build a platform in the bed to raise the camper 2-4 inches above the sidewalls and cab. Do this right and you can add some storage for long skinny things. I use homemade pallets, two for portability, and rubber mat between that and the camper. Done a lot of mountain passes some "bat stops" and have never felt underpowered, overloaded, or dangerous. I do have several years experience driving professionally under the worst of conditions in my past for whatever that's worth. Tailgate should be fine...but if your camper extends that far your center of gravity is probably too far back, and you WILL feel that. How much it affects handling depends on the truck. With my tires at 80lbs and airbags up to 60 my truck does fine. Were I you I'd look at one of the lightest model Hallmarks or get a bigger truck. Half tons are really made for towing, not hauling.
