It would seem like the most logical solution to your direction issue would be to swap the motor leads side to side on the motor terminals and swap headlight wiring end to end. That would make it act as if reverse was forward.
re: the cab. I took an H16 apart recently and there's multiple parts involved in the shell. I dont have a geep to mess with but from the picture maybe its the same way. There are screws that remove the battery boxes and walkway from the hood. There is also a series of tabs holding them together. The cab was glue to the walkway piece, like a saddle over the hood piece to hold everything together (I guess in case the screws weren't good enough?). See if you can find where it may be glued in, its cheap chinese glue and I was able to crack it apart by getting a finger nail in the seam with no damage at all to any of the glued parts.
