people will be searching ALL over this small place

Hopefully your clues are written so that when people get to the correct general location, they can immediately walk right up to the box and not be looking all over the place. If people have to hunt a pile of boulders, or a pile of logs, or check behind all the trees, that would be more like geocaching. The goal for letterboxing is to be precise enough so the boxer will see the correct spot immediately and not be searching for a needle in a haystack. Then you don't need to worry about finders accidently finding someone else's box instead of yours. Although there was that one boulder where I found 3 boxes a few months ago, each planter apparently not aware of the other boxes a few inches away.