Means (To go on) a long and tedious journey
Usage "Man we been trekkin' for hours!" "From her endz to our endz is a trek."
Collectors of Yoofspeak will know that in nearly every batch of new expressions offered up as authentic teen lingo, there are one or two which are not really slang at all. This is because most of the Yoof are not familiar with them and don't realise that they are standard English; also, to be fair, because they sound and look exotic, possibly subversive to the uninitiated.
"Trek", used more or less in its original sense, is a popular feature of playground complaints - the moaners wouldn't know that we got it from Afrikaans, and even Star Trek the prequel is a distant memory. Other examples of the same phenomenon are "luka" or "lookah", used by some London kids to mean money. It's really the picturesque old phrase "filthy lucre" after a makeover. "Burly", which was solemnly explained to me as a blend of "beautiful" and "gnarly", expresses admiration for a tough-looking man, and "reek" as in "Ben's locker really reeks" is considered a cool novelty.