I've got a letter talking about a secret money stash in amongst some rocks but I can't seem to find it anywhere and I'm beginning to wonder whether it exists. Help Please!

It's a ranger stronghold quest.

And that means what?

it means that to find this stash you first have to be a ranger, then you need to have got the ranger stronghold which will allow you to access this secret stash, and if you ain't a ranger forget about it cos' u can't get it.