Well it sounds like our interests are fairly similar. In regards to what route you should choose, my personal opinion is it depends on what skill set you want to acquire. Both international health and tropical medicine degrees will be useful in the type of work you are speaking about, but they differ greatly in the skills you will be able to apply.
With trop med you will learn how to recognize and treat tropical diseases (obviously) which can be highly useful abroad. Its a great adjunct to your coursework in medical school, and you will learn a good deal more about such diseases than your MD classmates. I have not had the opportunity to take any trop med courses so I can not really comment on whether medical management of such diseases is covered or if it is addressed purely from a public health standpoint. Its a great program as I'm sure you are aware. You can't get this degree anywhere else in the US.
With Trop med it is advisable to take at least some summer courses before first year as there are prerequisites for many of the courses and its good to start early. Its doable without the summer though, it just gives you less wiggle room. Trop med students have coursework they complete in their fourth year, while students in most other programs will have finished all classes before then. Its a commitment for sure, but I'd wager its quite worth it if you are really interested in international work.
International health covers a wide array of skills. One plus for the program is that there are very few core/required courses, allowing you to tailor the program to your needs (taking trop med courses if you like, or whatever). You can take a look at the course listings online to get a better idea, but you learn a lot about managing nutritional and various needs of various communities and refugee populations etc.
Both programs are great it really is up to preference. If i were to flat out make a recommendation I would say trop med, you'll have a degree that very few other individuals have, and I'm certain that opens quite a few doors. Regardless of which program, Tulane is very very well represented abroad. Trop med and international health grads are literally all over the place and I constantly here about Tulane "reunions" in even the most remote locations.
I chose to go an entirely different route with the disaster management track within the environmental health department. Again its a different skillset, and while I want to do a good bit of work abroad, I also wanted something that would be useful here in the states.
I also want to stress that the course load, regardless of the program, is more than manageable. The med school doesn't give letter grades anymore which helps as well, and its easy to find a balance between the two programs.
As for the 32k extra. I can't say that I don't ever have panic attacks when i think about how much debt I'm in. But honestly its the cheapest degree you will ever get. If you decided later you needed the MPH it will cost considerably more (and so so many physicians are going back for the degree). Its not your only chance though, as i feel i have to mention that a number of fellowships etc later on have an MPH or similar degree built into the program. In the end, i really feel that with the expansion of medical knowledge medical schools have been forced to neglect the public health aspect of the profession. Thus I feel the MPH is really that missing piece to becoming that traditional idea of a physician.
