Its a tricky one, but I think all the important stuff and suggestions have already been made.

Something I do, which is only useful if the "potential viewers" are not too computer savvy is to simply make sure all "files" you dont want found are hidden and that folder options is set to "do not show hidden files".

That way, when it is safe to do so, you simply change the option to show hidden files, mess with your "naughty files". Once done, REMEMBER to set back the folder options to "do not show" and your done.........simple and effective against most folks who in general don't know their way around PC's that well.