After a few game code hacks to bypass error codes, I was able to get the game to produce a "Out of Service" screen. From this screen I could get into the operator mode and setup all the game settings for denomination, sound, double-up etc. Basically, all operator mode screens became available.
After going through that setup I was able to get the normal game screen to appear with it showing cards from the last hand. With that screen I pressed "Play Credit" and it deducted credits and displayed 5 card backs like the picture shown here. I also re-ran the test with the "Max Credits" button and it peeled off 5 credits in a row like it should. I setup the ram to have 20,000 credits to start with in order to play.
Unfortunately, the "Deal-Spin-Start" button did not reveal the cards in my hand to allow me to press the Hold buttons. My theory at this point is the door sensors are still not 100%. I think they may pulse on/off instead of stay in a constant state. Either way, this is a major milestone.
Obviously I need to go back and find out what I need to do to remove the game code hacks, but being able to get this deep into the game is really helping document memory locations.