Bongo Fury

i'm looking to run wiring to the back of the van to power an amp as well as getting power to the head rest screens, sun visor screens and the multi changer under the middle seats, any suggestion on which way would be the best to run the cables? in the roof, in the side panels left or right hand side or both. will i need to take the seats out the back to do the install or will the panels come off by moving the seats forward and backwards.

I ran a cable to power 4 sockets in the back and did it via a fuse and switch in to he cab by driver (switch on dash) then to the side where the beeper connector is by your right footunder the footwell next to the door then tucked it under the side pannel.