The most common and most likely answer to this crossword clue is the 5 plus 3 letter word UNCLE TOM
U
N
C
L
E
T
O
M
More clues leading to the result UNCLE TOM
Buddy explains!

The straight part
We know that "Cabin dweller" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cabin dweller = uncle tom.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.