Four other mayors can be seen during the race. This implies that there are more towns than just Adventure Bay and Foggy Bottom.
In this episode, Ryder does not say "Whenever you're in trouble, just yelp (or whatever is substituted) for help!"
Gustavo Goodway makes his return in this episode, being credited as a "Guest", as this episode is his only appearance in Season 2. This makes him the first and only character to be credited as a guest (Oddly, the character is listed as a guest rather than a voice actor) in two different seasons.
Additionally, he is a participant in the race. This implies that he is also a mayor.