stray (away) (from something)
to drift away from or wander away from a particular topic or location. (The option elements cannot be transposed.) Please don't stray from the general area of discussion. Sally strayed away from her topic a number of times.
stray in(to something)
to wander into something. The deer strayed into the town and ruined almost everyone's garden. We left the gate open, and the cows strayed in and drank from the pond.
stray onto something
to wander onto an area, such as a parcel of land. Your cows strayed onto my land and ate my marigolds! If your horse strays onto my land one more time, it's my horse!