There are usually taxis readily available at the Fuerte Amador Port. Taking a taxi or traveling with a tour group is more convenient than walking. Your cruise line will likely have made prior arrangements for a tour group to be available. The tour groups have buses that allow passengers to see the sights in comfort. If you didn't make arrangements in advance, you can easily connect with a tour group at the port. If you need to wait for a taxi or tour for any reason, several shops and restaurants are located in the marina area at the port.
For more info, see Fuerte Amador Port Guide