Mostly to see how the PALs related to the Program ROMs I mapped out each pin on the program ROM:
Program ROM mapping on PCB 0333-01-F1
01-front left edge pin 37
02-front left edge pin 38
03-front left edge pin 48 & level shifter (U13)
04-front left edge pin 49 & level shifter (U13)
05-front left edge pin 50 & level shifter (U13)
06-front left edge pin 51 & level shifter (U13)
07-front left edge pin 52 & level shifter (U10)
08-front left edge pin 55 & level shifter (U10)
09-front left edge pin 54 & level shifter (U10)
10-front left edge pin 53 & level shifter (U10)
11- +5V
12- +5V
13- PAL (U4 Pin 22)
14-back right edge pin 18 & resistor array (RP4) & level shifter (U

15-back right edge pin 10 & resistor array (RP4) & level shifter (U6)
16-back right edge pin 17 & resistor array (RP4) & level shifter (U

17-back right edge pin 05 & resistor array (RP4) & level shifter (U6)
18-back right edge pin 16 & resistor array (RP4) & level shifter (U

19-back right edge pin 06 & resistor array (RP4) & level shifter (U6)
20-back right edge pin 15 & resistor array (RP4) & level shifter (U

21-back right edge pin 07 & resistor array (RP4) & level shifter (U6)
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22- GND
23-back right edge pin 14 & resistor array (RP6) & level shifter (U11)
24-back right edge pin 08 & resistor array (RP6) & level shifter (U9)
25-back right edge pin 13 & resistor array (RP6) & level shifter (U11)
26-back right edge pin 09 & resistor array (RP6) & level shifter (U9)
27-back right edge pin 12 & resistor array (RP6) & level shifter (U11)
28-back right edge pin 29 & resistor array (RP6) & level shifter (U9)
29-back right edge pin 11 & resistor array (RP6) & level shifter (U11)
30-back right edge pin 20 & resistor array (RP6) & level shifter (U9)
31- +5V
32- PAL (U4 Pin 21)
33-front left pin 39
34-front left edge pin 40 & level shifter (U15)
35-front left edge pin 41 & level shifter (U15)
36-back left edge pin 30 & front left edge pin 42 & level shifter (U15)
37-back left edge pin 27 & front left edge pin 43 & level shifter (U15)
38-back left edge pin 25 & front left edge pin 44 & level shifter (U14)
39-back left edge pin 24 & front left edge pin 45 & level shifter (U14)
40-back left edge pin 23 & front left edge pin 46 & level shifter (U14)
41-back left edge pin 22 & front left edge pin 47 & level shifter (U14)
42- PAL (U4 Pin 3)
nearly every Address and Data pin is routed to the edge connector in addition to a level shifter IC (most likely to be routed to the ASIC)
The exceptions are GVpp, A20, and A19, which are routed to the PAL and A18, A17, and A16 which are routed to the edge connector without a matching connection to the level shifter.
also interesting is that A8-A13 have 2 connections each on the edge connector.
the pal modifications seem to mostly bypass the PAL's control of of the last two address lines.
A20 is normally PAL controlled and we tie it high
A19 is normally PAL controlled and we tie it directly to the Edge connector
The only remaining connection between the program ROM and the PAL is Program ROM Pin 13 (GVpp)