cab mounts and crooked bed

[jesdude7789]

I've noticed for several months now that my whole bed has kind of a "bent" look to it. i'm the second owner of this truck and it has never been in a wreck since i bought it with 17,000 miles on it. but when i walk behind it and stand about 20 feet away and look at the "level plane" of the top of the bed the back left corner is higher than the rest like the whole bed has been twisted! what caused that? i do go out to a property in east texas where the truck can sit at a tilt one way or another because of where we're working on the land but would that permanently damage it? how should i fix this?

also the cab mounts need replaced and i dont know whether i want to go with rubber or polyurethane. the poly's are cheaper it seems. i'm worried that the polys would give me a harsher ride and allow more road noise to travel through the cab. what do ya'll think?