I do not know if you are going to install it yourself this time or not. Please advise.

It will be less work to sort out the existing harness. Wires are probably marked. The items you say that are "not hooked up", are very easy to "hook up". If it was an original rats nest or a bunch of PO add on wiring, I would say install a harness kit. It sounds like that was already done. Just take a deep breath and begin to sort. There are VERY FEW wires on an old truck. It will all straighten out quickly. We will help.

Nothing wrong with that Speedway harness. Good choice. There are quite a few unused wires. I believe there must be something obvious if so many things are not working.
1. How old is the installation? I see you said a few years ago on another post. So those item have not worked for years???? Not hooked up from day 1?
2. Are those items not working and you assume they are not hooked up or do you know for sure they are not wired?
3. You may be over reacting.
4. Are you unable to check and sort?
5. Are you unable to install a new harness?
6. Do you want help to sort and wire or do you just want a recommendation and that's all?
7. When you said insulation.......did you mean installation?

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn