When you agree to speak on cruise ships, your logistics are pretty well taken care of by the agency. That is one component of the fee you pay them. If the line is covering your airfare, they will do all the bookings and let you know the details. I still suggest you buy travel insurance in case you are bumped at the last minute. They have the right to do that. It happened to me. Since I gave them my credit card number, they paid the airline and I was therefore responsible for the cancellation fees. Aarrgghh.
Transfer from the destination airport and the ship can be a real pain. The line can arrange it for a fee. Usually about $60 each way. But if your flight is late, they will wait for you. If you do your own air and transfer (taxi?) – if the flight is delayed or you miss it – wave goodbye to the ship. Cruise ship speakers agency can assist here also.
Shots and visas are your responsibility. Check the itinerary if you are traveling to a port that has disease issues that may require shots. Malaria is a big deal. Take the treatment if you are going “backcountry.” Usually, if you are keeping near population you are fine – but check with the CDC on what is required. We are traveling to Jakarta soon on a cruise and a visa is required for Indonesia. The burden is on me to get them taken care of. You will not be allowed off the ship without one. Many lines make you get one anyway, in case there is an emergency and you must get off the ship. Not fun to sit for hours in a strange place.
Pay attention to the agency – they can be a great help.