If both trains and Africa are on your bucket list, consider travelling through Africa on trains. When I was in southern Africa for the Peace Corps 20 years ago, I travelled all over on trains. The first class sleeper cars were very comfortable and very cheap. I found it very easy to sleep on the trains, the motion seemed to help. All over Africa, they have these beautiful old trains. Back then, I think the cost for an overnight train trip in a first class sleeper car was about $2 US in places like Zimbabwe. I just checked and they are still quite cheap --- just $15 US for an overnight trip. It cost a bit more to take a train in South Africa from Joburg to Capetown, but still cheap and a great experience.