Eveready
I'm Awesome
Getting back to the OP's radio issue there appear to be two schools of thought at work here. If the OP wants just to have a decent radio that sounds better than his one speaker then 4 x 6 replacement speakers will do the job unless a lot of bass is desired. Cheap 4 x 6's will sound so much better than his 26 year old Delco that he might not notice the bass. Yes it is a huge pain in the ass as the Silverado trim will have to be removed to replace the rear speakers and to do that you have to start at the bottom near the seat belts. That would be the cheapest option and if the OEM radio is working properly it should all be OK.
The other school of thought is the new head unit, amp, sub, the whole mobile jukebox bit. If that is the object then the extra power, door panel install, sub in the back approach is the way to go. I was personally just happy to get a working radio in the truck and the bluetooth phone is a real plus. Since mine is a work truck I could just change out the 4 x 6 OEM speakers (all were open and dead) and install the new head and go. I chose a Kenwood because it matched the one in my Van and I already know all the controls. The OEM radio was dead with a frozen display.
I have a full set of the Silverado high trim to install and don't look forward to it . Good luck to the OP dealing with his.
The other school of thought is the new head unit, amp, sub, the whole mobile jukebox bit. If that is the object then the extra power, door panel install, sub in the back approach is the way to go. I was personally just happy to get a working radio in the truck and the bluetooth phone is a real plus. Since mine is a work truck I could just change out the 4 x 6 OEM speakers (all were open and dead) and install the new head and go. I chose a Kenwood because it matched the one in my Van and I already know all the controls. The OEM radio was dead with a frozen display.
I have a full set of the Silverado high trim to install and don't look forward to it . Good luck to the OP dealing with his.