I'm guessing here but I bet if it's a 6 inch lift it probably has a four inch suspension lift and two inch body lift. Getting rid of the body lift is easy. Unbolt and remove the puck like pieces and lower and rebolt. Suspension is most likely different a arms and torsion bars in front, blocks under the springs in the back. You would have to find some parts as well as new rims and tires.
Went through that phase and had a lifted truck. Worst truck I ever had. Looked great... As long as it sat in the driveway. Tires cost more. Suspension parts cost more. Cost more to turn those wheels. Cost more to clean. Cost more for purchase.
Doesn't seem like raising the trailer that much will be practical. My first thought is travel trailer instead. Will probably need a custom built ball mount as a standard one will never adjust that low.