Trailer.
I would not put a PA-14 on top of anything, as stated above it's heavy, not to mention awkward, and with accessories it's much easier to just put it on a trailer. Probably won't cost you any more for a trailer (used) than installing rack system and PVC on your truck. You only need to drop one of them once while trying to get it up on top of a vehicle to do serious damage to the kayak or yourself. Mine will carry two PA-14 with the second tier, which I made to be removable for the times I only transport the one kayak.