Good choice, as it's invariably the back that wears out first (condensation).
If you ever wish to put a 'short and sweet' muffler, here's a couple of pictures I took yesterday of the setup on my old rig.
Whatever you do, don't you comment on the rust and the state of decay of the system!!! That truck has lived more than 23 years in Quebec used daily in the salt and sand of winters and done more 600,000 in those conditions!!! It's under restoration now!!
Bon!!!
The pictures are simply meant to show how a simple muffler system can be made to fit in that space below the passenger seat, between the frame and rocker panel (what's left of it anyway
)
Chris