I looked at installing a backup camera in my 10 year old 4Runner a couple years back after a friend got me one for Christmas. After looking through a bunch of YouTube videos, we returned it. It was going to be a significant project.
Crutchfield will sell you a plug and play adapter from your factory radio to the new radio's pin outs. They do the wiring so you don't have to solder anything.
Having navigation and a backup camera definitely made it much nicer to drive.