I'm writing a novel that takes place in the deep South, (Alabama). I am from this area, and I definitely have a tiny bit of the accent. Some of my characters will speak like I do, others will have the deep south accent. I'm not having too much of a problem with it.

I think the best way for you would be the eternal: Fake it, til you feel it. Force it, and before long it will come naturally. I think editing it in would be a bad idea, because it would take along time, and be fairly difficult.

If all else fails, you can just not do it. People will still identify him if he speaks normally, but you throw in several cultural references.