Rear seat is easy enough. Pop the lower part out at the front, then remember to disconnect all the wiring harnesses. The upper back seat takes 2 people in my opinion. Once you get it unbolted, just a couple at the bottom I recall, you have to slide it up about 2 inches to get it off the metal hooks on both sides. Because of the curve of the seat, and all the padding, it's not easy to do by yourself, as you can't keep one side up, then get the other. Once both hooks are cleared, it comes right out, has a couple wiring harnesses also (heated seats). After that, I've only ever lifted up the back panel, looking for a few noises where the panel was rubbing/clicking. I was able to solve all of that.
That said, I can understand the doors, and back seat area, but I wouldn't recommend going all out to deaden the floor too. That said, Insulating the trunk floor would be a good idea. Long trips the exhaust seems to really heat up the floor in there...