Often forgotten is the fact that Cherokees and some others in the civilized tribes had Negro slaves. Some moved with them to Indian Territory when they were cleared from their farms and homes by prejudice and politics. There is a hamlet in Oklahoma that was started by these slaves.

As shown by several threads, the direction and guide songs exist mostly in the minds of people who have not studied the world of the American slave and think that slaves had the intelligence level of a mentally challanged mule. There are several narratives written or orally communicated by escaped slaves, and the information they used was more complex. Assertions about these "guide" songs are nearly all 20th century.
The world of the slave was much broader than many presume. House slaves knew the household gossip and information and passed it on. Slaves drove haulage for the plantations, worked on the steamboats (even sailing vessels), were hired out by the owners for a variety of jobs, some quite skilled, usually had once-a-week get-togethers at which information could be passed along. Even the lowest of the field hands had contact with house slaves and often with slaves from nearby plantations. The information that they had would be much more complete and not diseminated by song.

Of course there would be "signals" about "passage" on the underground railway, but these could be anything and were undoubtedly changed for each opportunity and passed by word of mouth, to be changed for the next opportunity. Moreover, only very small groups attempted the trip- in secrecy from the majority of the slaves in the area.