So you have a big double DIN reciever there now and are installing a single DIN and there will be a hole? If I'm understanding that right, call crutchfield, tell them what you''re trying to do and they'll hook you up with what you need.
I got a deck off crutchfield too, they sent me that pocket thing you're talking about even though I didn't need it.
Since I had an extra one I decided to try and have a little fun. I created a spot for my aftermarket switches - fog lights, neons, amp cut-off (in case a cop pulls up next to me at the light). It looks better in real life then in the pic, trust me. I included the attachment.
The pocket goes below the radio. It is just used for storage (but is too small to really put anything in). The deck that came installed in your truck will have 2 brackets (one on each side of your radio) that you will need to remove with a screwdriver and reuse on your new deck. All you will need is a wiring harness for the install. If you do replace a double din radio with a single din one, then you should also look for one of those pockets too before installing it.
I replaced the double DIN unit with my single Alpine CD deck. I got the pocket for underneath the deck straight from the Toyota parts department at the dealership. It costs about $25 and should tie into any quality aftermarket deck without any mods.
there is a kit for your truck I got one. Just got to any stereo place and ask them for a instalation kit for your year taco. It costed me $15 and it works and looks fine. My kit even has a spot for an eq if I decide to get one.