I have not done this for a cruise but used to live in Brevard County. The Melbourne airport is physically closer to Port Canaveral than Orlando but Orlando access is easier. It is a straight shot across a road called the Bee Line from MCO (Orlando) to the port. There are several shuttle companies that would get you from the airport o cruise port or the Cape Canaveral / Cocoa Beach hotels. There might be a few shuttles (Space Coast Shuttle comes to mind) you could schedule out of Melbourne. The local transit (Space Coast Area Transit Brevard
) does serve the Melbourne airport, if you are a patient type. Though I am not sure if the beach trolley goes to the port.