If the 4 states have to be in a specific order say ABCD, then the total number of different possible routes is:
43P4 = 2,961,840
So the probability is:
1 / 2,961,840 = 3.38 x 10^-7
But if the 4 states can be in any order such as DBAC, ACBD etc, then the total number of different possible routes is:
43C4 = 123,410
So the probability is:
1 / 123,410 = 8.1 x 10^-6
No I don’t think it is practical to list all the different possible routes to select the one that is best. We can simply use mathematical models to solve for that one.