TW: autism. I enjoyed listening to the song while in rains of Africa, so here's my alternative explanation, using 5E:
I hear the drums echoing tonight But she hears only whispers of some quiet conversation
Clearly a 1st level Ranger using Natural Explorer, so they're in his favored terrain (grassland).
She's coming in, 12:30 flight The moonlit wings reflect the stars that guide me towards salvation
Taking the Keen Mind feat could still be 1st level human if Variant Trait, or 4th level of any other race. Natural Explorer again provides ability to never become lost.
I stopped an old man along the way Hoping to find some long forgotten words or ancient melodies He turned to me as if to say, "Hurry boy, it's waiting there for you"
Favored Enemy makes tracking old men quite easy, still only a 1st level Ranger. The understanding of the man's gestures can be chalked up to Favored Enemy providing Language (Old Man Gestures), as is the use of Intelligence checks to recall information that old men might possess.
It's gonna take a lot to take me away from you There's nothing that a hundred men or more could ever do
Now, I differ from the original poster here in that I think Toto is discussing a future state, as in "much effort will be needed to prevent me from following you". We return to Natural Explorer's ability to track other creatures and known exact numbers and when they passed through. Coupled with Keen Mind and Favored Enemy, he could detect your presence even among a moving column of a hundred men (or more).
I bless the rains down in Africa Gonna take some time to do the things we never had
We haven't talked background yet. Acolyte would give you a holy symbol plus Religion and a prayer wheel. Given that there isn't really any way to effectivel create holy water as rain short of epic casting, this seems reasonable. Also, a holy man forced to hunt his fellow man to recover a missing woman would presumably like to take a little time to engage in religious ceremony.
The wild dogs cry out in the night As they grow restless, longing for some solitary company
Speak With Animals is all that's needed to understand that the dogs are seeking to bury bones. Unfortunately, this brings us up to 2nd level (or reflects the alternate 4th level Toto already in progress).
I know that I must do what's right As sure as Kilimanjaro rises like Olympus above the Serengeti
Doubling that proficiency bonus on Nature checks with natural Explorer would definitely reveal major features. Religion and the Acolyte background provides a plausible explanation for knowing a holy mountain on a different continent.
I seek to cure what's deep inside, frightened of this thing that I've become
Our low level adventurer tracks and hunts. He levels up. The only way to readily defeat the terror over becoming a monster who kills Men and Old Men is by specializing as a Hunter, then taking Defensive Tactics at 7th level choosing Steel Will.
We see Toto over the course of the song going from likely a priest, perhaps sweet on a nun, to a hardened killer who ranges across the grasslands like a deadly scythe. It's tragic and beautiful.