I assume wandering monsters are not in lair. The outdoorsy characters can then have a chance to follow the signs leading back to the lair, possibly finding the kin of the first encounter. In the old days, whole adventures were created out of tracking creatures back to the lair. In dungeons (way back in the day) lots of rooms were empty and could be used for the lair of wandering monsters. This is the way we did it.
“How can I wear the harness of toil
And sweat at the daily round,
While in my soul forever
The drums of Pictdom sound?”