A tweaker is a methamphetamine addict. Rode hard is short for “rode hard and put up wet” which is a horseriding term meaning “put to repeated and very hard use without proper maintenance.”
You may apply in the neighborhood of any crack house or drug den, but I would advise strongly against it. Think “Crack whore” and you’re on the right track.
On a side note, it occurred to me later that an addemdum to your question is in order. I also have been propositioned numerous times (a dozen or so), without any mention of the fare being made. I’ve also passed on these, as it would strongly cut into my money-making time.
