a ho-dunk is a shitty small hick backwoods town, where theres only one or less stop light in the whole town. The villagers are hideous miscreations of God that inhabit the surrounding area, and usually helplessly addicted to crystal meth. Also everyone in town not only knows each other, but are also related in some way.
Billy Bob: wow! there's nothing to do here in this town besides freebase crystal meth and fish!
Jim Bob: yup! this sure is a ho-dunk!