OK! Thank you so much for taking the time with this, especially the image. I will try to match up what you are describing withe the schems and do some probing. i really appreciate the hand-holding and hope it pays off with another rescued SE/30. I am also feeling better about my decision to get the desoldering alloy so I can do a better job of cleanup around and under the ASC. More to come, I am sure, but this answers a lot.
A0, A1, A2, and so on are the address lines. You have 32 of them.
When looking at the schematics you will see the signal name (let's take A0 for example) and the corresponding pin number (pin A2 in case of A0, pin C4 for A1, pin D13 for A2...)
When you flip pages to the video section you will see that A0 should be present at pin 4 of UD8 as well. Put your probes on pin A2 of the CPU and pin 4 of UD8 and you should get continuity between those two.
Repeat with all other address lines that are present in the video section but as said you usually have A0 or A1 broken because that's where the cap goo is getting most of the time:
The breaks usually occur where the traces enter the solder pads of the ASC or for A0 where the trace enters the solder pad of UD8.
Because you also have issues with your audio I would suspect the breaks to be where I put the little blue marker.
The big blue circle is where the cap goo usually spreads.