Hmmm...this is probably too much of a hack to code, but perhaps it will
stimulate discussion...
Rumours!
Hide 'specials' wherever you want. Create a file of 'rumours' that
hint at their location, or anything else you want to hint at (doesn't
have to be true!). Then think of a way of giving them out randomly in
a way that favours explorer-type people.
For example, every time a noble enters a city that he's never been to
before, have a small (a few %) chance of hearing a rumour. Or just
have a tiny percentage chance every time you enter a new province.
Or have a new 'object', a rumour! Then players who can explore
can be told they've found one.
For more finesse you could have a different rumour file for each major
continent!
You can then indulge yourself with hiding locations, artifacts, scrolls...
Chris
-- Chria Yearsley cmy@cs.keele.ac.uk