I need to make a long haul (3500 miles) from the lower South east to the Northwest, I need to haul two trailers on a flatbed trailer appro 45' long. I will be doing it with a '03 Silverado with a 5.3L Vortec Engine . Does anyone know if a faltbed towable trailer or a goose neck would be better?

 

My brother does the same type of hauling that you are talking about. He started out with a regular bumper pull trailer but ended up swapping over to a gooseneck trailer because they have a less chance to wip on you. They also put the weight over your axles for better handling. With gooseneck/5th wheel trailers you don't have to spend as much time trying to make sure the weight is sitting just right on the trailer.