Nice idea! But, how about making it a two-parter? First part is finding the map and starting the hunt, and the second part they solve more clues and meet the ghost. And maybe have the ghost teach them a lesson about history or sth? Cap'n Turbot would eat that up.

I am all for a Cap'n Turbot centered episode! Pups Stop a Huge Rock could show off his quirky intellect and bring in some cool underwater rescue gear. Maybe even a new vehicle? But the whole ladder store thing, kinda random XD