I have the nasty feeling that I'm going to have to explore every corner of every map with stealth on so I can discover all the item caches. Is it worth it to do that? It'll make things pretty slow unless I'm double-timing stealth movement.
I'm even finding item cache(s) in town area(s) for example.
This one will eat away at me as well. You could always clear an area first then fast forward through it in stealth.
I forgot what area this was, but I recall finding a piece of paper that basically said "Watch out for these rare boots in this area!" Wish the hidden items were handled a bit like that. Clues somewhere in some form.