Ok, I have quite a bit of experience with stereos in the older C/K trucks. First off, you can get the cubby hole thingy at a junkyard. They came in the base model trucks that did not have a stereo. Second, the stock stereo consists of three components: the control panel (just to the right of the steering wheel) the main unit (under the dash) and the tape deck. There is not enough room next to the steering wheel to mount a head unit there, so it MUST go in the place of the tape deck. You will have to by a dash kit that replaces the panel where the tape deck is, and it will allow you to mount any single DINN head unit there. You will also need the wire harness adaptor so you don't have to cut the harness in the truck. All you will have to do is connect the harness to the wires comming out of the harness for the new stereo, then plug the other end into the three little harnesses in the truck (you have to disconnect them from the main unit under the dash) You will not have to remove the main unit that is hidden under the dash, it can be left in the truck if you want to. It's pretty easy to do this, it just takes some time. Hope this helps. I will get some links for you in a few, so you will know where to get the dash kit and wire harness.
Well since you have the knowledge, Maybe you can help me out. I have the same stereo set up in a '93. Not working though. I got a whole other stereo (all 3 parts) and replaced them all. No luck. When I started driving the truck, only one of the dash speakers was working. I'm not getting an sound at all now. Not even static. Blown speakers mabey? I know this a common problem and I've seen it before but still haven't found an answer.