While two oxen are not the sort of prey a small wolf pack likes to contemplate, there are other predators prowling the bushes, as recent events, and discoveries, make clear. The underbrush is light enough, and the trees thick enough that you could conceal the cart off the path. Taking two oxen and a large cart down a trail meant for goblin raiders would not be easy. Although, again, given the general lack of underbrush, it is possible. On the other hand, the possibility of bandits, monsters, or packs of ordinary (or not so ordinary) animals looms. As a final note, six goblins probably wouldn't want to drag a dwarf and a human for very long.
Certainly, the whole assemble can't be left sitting in the middle of the road. For one thing, the oxen would have nothing to eat.