You make it sound much harder than it is...
These trucks, atleast the 2003-2006, are very easy to work on for the car audio. The front door is like 3 bolts, a couple plastic pieces that have to come off and the door panel slides right off. Very simple. The front speakers are easy to do too if you have an adapter or can build one. I used a dremel and cut the old blown speakers off the mounting ring and was able to reuse the outer ring. The rear doors are easier yet. I believe just two bolts. The console I already mentioned.
The center console sub is ONLY a 6" DVC sub. You can get door speakers that put out more bass. I haven't had the time but I have considered putting 6" subs in the front doors along with the front speakers I have now. Would be nice for some extra bass. I also dynamated my front doors. Although no sense to cover holes as dynamat is a sound deadener not a sound proofer. Just cut holes where the holes are and you are fine.
The center console is removed as I mentioned. You CAN replace the rear seat audio controls with a storage pocket too or other setup. I plan to use one of my old phones and incorporate it like a tablet. Phone will also provide a hotspot as well as be connected to my PC.
Rodney