There should be some pretty decent fishing around HHI in October. There are some near shore reefs (7-10 miles), but probably not wise for a 17' boat with small children. If you decide to go on a calm day, two possibilities are the Gordon reef and the Fish America reef.
There is an artificial reef near Parris Is in the Broad River. You should catch black sea bass and sea trout there. You might want to get a reef anchor or risk losing yours.
Trout and redfish can be caught in the creeks around HHI. A float with shrimp or live mud minnows is best. If you like artificial lures, try Berkeleys scented Gulp. Look for points with oyster shell banks. You might want to ask some locals over there for some locations( if they are willing to tell

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Have fun and enjoy your vacation.