It's really not that much work. I installed 6X9's in the rear package shelf which was probably the worst part. If you're sticking with the door locations, you don't have to mess with the 3rd brake light or the package tray.
I would suggest pulling the rear seat to run the wires. You can snake them into the trunk without removing the upper portion of the seat but it might take a little effort. I found plenty of room to run all 8 wires tucked under the door sill plates on the drivers side, so I didn't have to pull the carpet.
The only panel that has to be removed in the trunk is the one that covers the seat back and the underside of the package shelf. There are only a few fasteners to remove. You'll see a few staring right at you on the vertical surface directly below the trunk weatherstripping. If you lie on your back in the trunk you should see 2 more a few inches back. Pull these and the whole panel will come out in one piece.
What's left is a big plastic chassis with the whole amp assembly inside. Pull 2 more push in fasteners and it will swing down. On the right side of the amp is a connector with the following color wires:
From the factory EVTM:
RR door BR/PK- and O/R+
LR door T/Y- and GY/LB+
RF door DG/O- and W/LG+
LF door LB/W- and O/LG+
If you're in doubt about the polarity, you can touch the leads from one speaker to the + and - terminals of a 9V battery. If the polarity is correct the speaker cone will rise away from the magnet. If you have it reversed, the cone will pull down toward the magnet.
Unplug it and either attach your aftermarket harness or cut/strip/solder/shrink to the wires.
I don't have a link to the Crutchfield harness, but you might be able to dig around on the website and find it. Remember that if you buy the bypass harness, you'll want to plug the harness in and run the wires forward to the dash. It would be more work to start at the dash and try to snake the big connector through the dash and back seat. If you're just going to string speaker wire, you can start on either end
Keep in mind that this was all correct for my car but some things might be different for your, particularly if you have a different factory audio system.
If you lived closer I would offer to give you a hand. Good luck.