FXE (lauderdale executive) is a very common point of entry, now open late. File Notice of arrival with US customs at least 1 hour before arriving, make sure you arrive close to that time at the customs office. Make sure if you have to file an APIS (might be just for comml operators-135, I don't know), also an hour before arriving. Make sure everybody has a birth certificate or passport before leaving the US. Avoiding the big airports in the US and the Bahamas is a good way to avoid hefty landing fees. Call ahead for fuel, call ahead for customs at small Bahamian islands is a good idea too. Inter island you need a stamped transire. VFR interisland you need to file a flight plan, opening can be a pain, make sure you close them too. Coming back to the US file flight plan, either with Miami FSS (Bahamian airports have dedicated telephones for customs, flight cervice), or with the flight service office (Nassau, Freeport), open it and when VFR get customs squake code before entering ADIZ. IFR Miami center will issue you a squake for radar identification and customs. No fruit or vegetables back to the us. Frozen fish is OK. Customs might cut a few up to check for illegal stuff. Know limits on imports (tabacco, alcohol).
Get a US customs decal (sticker), plenty of general declarations (3 outbound, 3 inbound and the Bahamas flight guide (about $40.- a couple of years ago), plenty of cash. US dollar is one to one with Bahamian.
When arriving in the US every piece of baggage has to come out of the aircraft.
Have fun