Solution TL;DR(264)
Where and How
The solution to the keypad in Gator Zone is not so much found as it is "hidden in plain sight." It is not uncommon to assume that we might find the solution to the keypad either in the immediate area around the shack or somewhere else in Gator Zone.
This, however,is not the case; upon having payed closer attention the player may find that the in the case of the keypad:
the problem is, in fact, also the solution or rather hides the solution.
So in order to unlock the building: 1 of 2 possible routes may be taken by the player.
1st Option
Feeling lucky? Are you a gambling man? Or, are you living proof that stands to attest that generational inbreeding amongst humans has turned you into a chimpanzee that likes pressing buttons for the sheer gratification of firing up the old dopamine sectors of your brain? A dopamine hit that you will achieve when you somehow manage to by either means of elimination or just sheer luck find the 1 in 1000(literally) solution to your question?
2nd Option
Focus and look at your problem calmly, like a detective. You will notice that the #'s are flashing in a repeating pattern. These flashes (in number) are directly linked to their corresponding numbers which you may briefly enter into the keypad in order to unlock the door.
Hope you enjoyed the read!
Source: https://steamcommunity.com/sharedfiles/filedetails/?id=2981504124