I'm a vol. fireman also and have a Whelen box under the drivers seat. I built a harness that travels along the rocker panel, up the left kick panel and ends in switches mounted in the knee pad to the left of the steering column. One switch is on-off, the other is a SPDT center off momentary to toggle the flash pattern and hi-lo brightness features built into the strobe box. I have a Dashmiser on the dash and one small strobe mounted just forward of the duallies on each side (they are really meant for Crown Vic grilles, but are nice and small). Power is fed through a Painless add on fuse box.
As if a 3500 4x4 dually wasn't intimidating enough - try one with four strobes going and the Grovers screaming!!!!!!