"Where do you know about that route from?" sounds more natural to me, but it's not accepted.
should from where do you know of that route be accepted
I suspect this translation is wrong... but I genuinely don't know what it should be. Should it be "from where do you know this route" or "where did you get to know this route"?
Should be from where methinks
Can it be "know thus route" without"about"?