This is a very fluffy suggestion but with all the faction funny business and secrecy going on lately, got hit with a sudden thought:

If burrows might ever have the same kind of name-learning quality and optional setting descriptions as critters do! That way secretive places would really have to spread by word of mouth for folks to easily find it. And you might put something like "this place smells of herbs" or "you can see a light from the entrance" etc to give it whatever flavor you'd like. Possibly even having a signpost out front would automatically inform a critter of the burrow name if they can read and haven't heard it spoken aloud. And silly name changes, if someone already knows it as the previous name it won't update.