Vampire Coast Treasure Maps.

[Omrah]

is there a guide to the locations where all the buried treasures are?

[Hex]

They are random and you need the maps for them to appear. If there was a guide, google search would tell you.

[unless specifically stated]

You can click on the magnifying glass button and it will zoom precisely where the treasure is buried.

[KoboldUtopian]

Unfortunately, they're almost never worth getting. You'll spend way more paying a hero to go over there than you will ever find in the chest.

[fenlander]

Only go for a Treasure Chest if you're in the area. They are not worth it in TW3.
Vampire Coasts need new campaign mechanics in my opinion. Power level and lords are fine as is.