Thank you! I should move to the digital colouring in the weekend.
I plan to add various "travel notes", some serious ones and some easter eggs hidden around.

Some ideas so far:

Volcano:
A village with a “visited the day X, everyone is now missing”
An area “lava flow covered mr Banks”
Mr White and Mr Coombs fell in the lava. They are fine now.

Archipelago:
This island wasn’t there last time

Open Sea:
Several notes day after day.
Mr Tobbs saw a vessel. Nothing found.
Mr Tobbs noticed a fire. No fire found.
Mr Tobbs noticed a blue whale. The whale is now hidden
Mr Tobbs killed by the crew after noticing a sparkle of gold.