In the song he mentions “You can take me to Moisty Mire”, which makes the rift theory impossible because Paradise Palms replaced Moisty at the beginning of Season 5, where the rifts were added.

Edit: After wiping out Tomato Town with ten kills on the board, this must be rather late in the game. The Storm will have already formed. So when he heads southbound, he ends up in Dusty Divot (possible within the timeframe we have set), and sees that the circle has moved to the northwest corner of the map. He grabs a hop rock from the crater, then crosses the south river to swing around Loot Lake (he despises Loot Lake) and end up in Pleasant Park. The mystery is solved.

Edit number 2: After further research, it appears that later in the song he mentions an ‘ATK’. This may not be the same song, but if it is, then a paradox is created as the ATK and Moisty Mire have never existed within the same point of time. This leads me to believe that the singer is a reality-bending time god who took the persona of a child, and made his own bootleg version of Fortnite so he could learn how to play and connect with the mortals upon his arrival on Earth.