As far as getting power, here's my setup. Originally I had stuff spliced into cig. lighters, but once I got some offroad lights, I redid everything as it's much cleaner and easier to add stuff later on.

I ran pos/neg from the battery to a marine fuse block



and from there one of the circuits is used for inside stuff. I ran a set of wires inside the cab through one of the premade holes to a small distribution block. (found some sheet metal lying around, tapped holes for the block and drilled a hole for the big mounting bolt)



On the top, red sheath=pos, blue sheath=neg, so I have 3 power terminals to run stuff off of. Mounting location is just past the e-brake assembly.

As far as CB cable lengths go, 18 ft is most popular, but if it's way too long get something smaller. It's not that crucial. Just make sure the cable is designed for CB use at that length and it's not just an 18 footer cut up.