I am more than happy to be asked to give talks about my trip. :-)
Generally, my presentation is geared for 45 minutes (or so) giving an overview of the whole trip.
Some talks have taken a single country and given a more detailed account of that.
Or, as a further option, a single continent could be the focus of the talk.
I am also happy to give talks on The Leprosy Mission (I am a local speaker).
Contact me on: firstname.lastname@example.org