Search:

I'm pretty sure that "куда ты ходил?" by itself can be understood as referring to a single trip there and back -- because a round-trip is, by definition, not in one direction only!

But "куда ты...

Here are my translations:

RIDING IN A VEHICLE OR ON A HORSE, ETC.
куда ты ехал (кодга ты НЛО увидел)? Where were you going at the time when you spotted the UFO?
куда ты поехал? Where are you...