If you're heading down US 1 to Key West, some of the old bridges in the "Overseas Highway" have been converted to Fishing piers. A few of the more popular ones are the old bridges on Channel #2 and Channel #5 around mile markers 70 to 72. On these bridges you may fish on the Gulf of Mexico on one side and the Atlantic on the other side. Another popular one is the old Seven Mile bridge.
For a change of scenery you may detour on to Card Sound Road from US1 which will take you back to US 1 and pass through a fishing Village with a tavern where the "Alabama Jacks" play and it will also take you through a Crocodile sanctuary. Some good fishing and crabbing on this route too. Just watch for the folks on the short bridges making their casts or cars parked on the side of the road with their owners fishing nearby creeks with brackish water.