The posted coordinates are for the Hackley/Hume Complex
It won't help to find the cache but it is some Muskegon history you may want to visit.
In order to find the cache you must complete the associated Adventure Lab.
Make sure you keep track of date of death for the 4 individuals whose graves you visit (one is a family mausoleum)
Take the last 2 digits of the year of death and put them in the checker in alphabetical order (no spaces).
(You should have an eight digit number)
https://adventurelab.page.link/7jLp
The final and the Adventure Lab are in a cemetery so no night caching.
You can validate your puzzle solution with certitude.