Help with vac hose connections - 1977 w/250

[D13]

1977 C10 250 six manual trans 1bbl integrated head. This thing is soo boogered I have little idea what goes where, I just know it doesn't go where it was (sticks, screws, loose, etc.) Looking for help! Need a diagram or even words.
I know the PCV goes to the big tube on the Y on the mainfold. (side note - wish they had run a breather and replaced the rotting grommets, I took about a cup of sand out of the valve cover).
The cannister purge line looks like it goes to that same Y (since it's labelled PCV).
The fuel vapor hose is hooked to the cannister, that's good.
The third cannister hose look like it's hooked to the EGR (in front of carb)?
There is a small hard vac line that runs around the back of the engine to a switch, this is capped at the switch and open in the carb area. Any idea what that is? Where did it hook up?
The distributor advance vac hose was clipped to the fuel line and appears to come from the Y on the carb base. This would be ported vacuum?
So that leaves:
One small open port in the rear of the intake (capped with hose and screw), I suspect this is where the line that goes behind the engine hooked originally.
The EFE valve (behind the carb)(capped with hose and stick) (not even a golf tee like civilized mechanics use!).
One leg of the Y in the carb base.

Help!