I just recently did a complete overhaul. The doors arent as bad as you think. At first glance they look impossible but once you remove the boots and you will see there are open spots in the plastic wiring harness for you to fish your wire through it helps a ton.
I placed my amps under the rear tire well standing up in corners needed a little trimming with the dremmel. Also made to vent holes and attached computer fans to circulate the air.
I removed both passenger seat and rear pass seat for install. it helps to route the wires gorilla taped to the floor keeping the power away from the RCA's also Dynamted the door speakers and whole back end. Also added to tweeters in the front center cut to holes in the vent shroud placed them right next to each other. It helps with imaging and staging.
I have to say that truck is put together very well. the sound deadening used is pretty well done. All in all about 15 hours of install time then about an hour of tunning.