I think that sentence structure and the way that words are delivered changes a lot when it comes to the South. Not just for their location, but also what economic status you come from. My Grandmother was from Kentucky/West Virginia, but she was from like the absolute sticks, so she had this crazy thick accent and she'd use words I haven't heard anywhere else (like using "hollar" as a unit of measurement.) Instead of saying "I'm gonna go on a walk" she'd say "I'mma go a-walkin'." (I dunno if this is an Alabama thing, though)
So I don't think an accent needs to be written out word for word, but occasionally you do get a word where it's like "no one would say creek in this part of the world" and you would write out "crick". And then you get other words like "I'mma" and it's like...well that's not even a word so I guess I have to write that phonetically. But overall, the sing-song quality of a sentence is what sells it for me as a southern accent, which is more about the phrasing of an entire sentence than accents on specific words.
Also, sometimes it's helpful to read what info linguists have collected on grammar usage in whatever dialect of english you're looking at. So like this page on the Southern accent gives a lot of helpful tips. https://en.wikipedia.org/wiki/Southern_American_English#Multiple_modals A shame they don't have specifically Alabama.