Thanks for the sentence but it does not seem to be written by a native speaker as there are errors in it, and the meaning is unclear.
"As far as that town's people can go, she is pretty not terrible."
The usual use of "pretty" as an adverb that qualifies an adjective would be:
"As far as the town's people go, she is pretty terrible" = "As far as the town's people go, she is quite terrible."
If you want to change that to a negative:
"As far as the town's people go, she is notpretty terrible" but this must either be (i) a response to a previous statement or (ii) must be followed by, e.g. "she is really pretty/quite good."
As an alternative,
"As far as the town's people can go, she is pretty, not terrible." = "As far as the town's people go, she is pretty,she is not terrible."
Problem is I can't contact with her right now, that's why I'm here
Thank you but actually imo, it doesn't have anything to do with this sentence.
And no I can't give you whole context because dialogue ends in here and the only part they've mentioned this only in this sentence. From my point of view, someonelse is mentioning ''townspeople and how far they can go (mentioning about their negative sides) and saying the person in this sentence //she// is pretty not terrible'' ... I mean is speaker here actually trying to say ''she has negative sides but she's not so bad as townspeople'' or is it the other way around? I'm really confused.
Uh, but the thing is there's no revelant sentence to this one. While character was describing her friend the first sentence is this. Then in latter sentence, he talks about how she's hanging out with some people (with bullies according to him) but she's usually lonely,like him etc.
Without any context, it's impossible to know whether this was an error on the writer's part (as seems likely from the other errors in the sentence), or creative wordplay, as Loob has suggested. This thread is therefore closed. Thank you to all who participated in the discussion.