clue four: answer and walkthrough

 By 8th and main near the capitol grounds, There are two years to find on the ship mural.  One is the date the ship set sail while the other is the date the mural was created.  Using these dates, you’ll be able to shift the coded letters in alphabetical sequence.  “+” means forward in the alphabet (e.g., A, B, C, D…) and “-” means backward in the alphabet (e.g., C, B, A, Z, Y…). Once you’ve applied the shift to “TYEJ,” you’ll find your answer: “SEEK”