if it isn't new then i would definitely go with a gooseneck coupler on that trailer. i don't know were your at,but if you can't find somebody to build one for you,there are a couple of manufacturers that build a couple of different type of slide in couplers to replace the kingpin. some of them are set back to help with a short bed. but the best way is to back your truck up to it with the trailer level,putting the king pin right over your ball to get your measurements. then just have a welding shop build you one custom with a bull dog coupler,but i prefer the kaylin coupler because they don't get banged up and don't have any moving parts to get broke or bent.