A gutter mount is a good place for the antenna but is a bit harder to route the cable.
There are some mounts designed to clamp onto the tailgate with a short pig tail of really small coax that will fit through the gap between the tailgate and the body so you can run it all the way down the side of the tailgate go underneath and then bring it inside somewhere.
If you have a front bumper with bar work then the antenna tab on those works quite well and it's easy to get the cable into the cab.
I don't body mount antenna just because plans change and suddenly you realise the antenna mount is in the way or covered over by your new plan
