if you have been wheeling it I'd check the tie-rod first
a slightly bent tie rod will cause it to toe out alot and that causes big time wandering
I would all grab the top of each front wheel and shake it hard and check for play, a bad or loose wheel bearing will also cause nthem to hunt for even the smallest line in the road.
both those check out I would check the steering gear for to much play, a small tightening of the steering gear at the arbor screw will very often calm down some wander. but dont over do it or the box will die a fast death.
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of course check all the rod ends for slop...they wont often cause wander but when they fail life can end so while your there...check them