To receive the appointment letter, it is better to request both Package 3 and 4 via email - BridgetownIV@state.gov as the postal services are not the most reliable. You can submit the request for Package 4 with a scanned copy of your signature and the date
When assembling your documentation, pay close attention to Package 3 and the medicial information in Package 4. However, the actual documentation is listed on this website (http://barbados.usembassy.gov/iv-k_1_visas.html). It is not explict in the Package 3 or 4. Note that I was approved but I had no idea that I had to submit two additional documents, including one that I had to request from another country. This cause a delay in issuing of my visa.
When going to the Embassy, there are four checkpoints. Although, you are applying for a K-1 visa. It is considered under the Green Card category. So mention this at the checkpoints to avoid confusion.
Consulate / USCIS Member Review #18282
Review on November 4, 2015:
