Yeah, this seems like a no-brainer since the caravan spawns for the quest and already has a destination from the get-go, so the questgiver could just tell you its a caravan bound for x and y locations and you can decide if its worth the trip. They do sometimes change their mind on the way if the path's blocked or conditions change, but that's fine as an unexpected wrinkle.
On a related note, I really wish they'd tell you ahead of time how long it will take when you send a companion out on a quest. A few of the quests tell you how long and how many troops they need, but most don't and you only find out after the fact that your guy will be gone with half your army for a month.