It looks intimidating but removing the head is key to getting a game up my stairs as gravity is working against you.
You can either use a sharpie to write on the connectors or use some masking tape to write the connector number on. Most people will say the connectors are keyed anyways but I still think it is better to take the few minutes to label so that way when you are putting things back together you do not have to guess or make any assumptions and risk messing something up. As you do this more you will learn which connectors you do not need to bother labeling or disconnecting such as the backbox GI connector or backbox speakers.
Also if you have everything unplugged you can pull the play field out completely from the cab to make it lighter and easier to move down without any additional work. You just have to be careful and take your time handling the play field and set it in a safe place on its side as you do not want to rest the weight on say a coil bracket. DE, Sega and Stern games are easy to remove the playfield but Bally and Williams games have a hinge and latch you need to release and snap back in place. After a few you will get the hang of it I am sure.