The key is to do some exploring with a fish tape to find out where you can and can not run wiring. Once you know where it's going pull a messenger line with the fish tape and then pull one with every wire you pull so you will alwys have one there. I installed a trolling motor, a HB on the bow and another one on the console and networked them all together with ethernet. I think my total time was around five hours, so it does take time to do it right, but if you do you won't be wasting time later chasing down phantom electrical problems. A label maker for marking wires as you run them is a worthwhile investment. I've done complete wiring upgrades on old Chris Crafts and I can tell you there is no fast way to do it right and cheap and reliable do not work well together when doing electrical on a boat. Usr quality wire and components. You won't be sorry you spent a little bit more.
2015 Seaark 1872 MV CC Etec-90
Two Helix 12 CHIRP SI's, , MinnKota Riptide ST80/i-pilot Link, Bob's Hydraulic
Bitter Gun Owner