I took time off the travel/research between my 3rd and 4th year. And I just found out yesterday that I matched into Gen Surg into a university program.
Thought it is not the most competitive residency around, they are traditional. My advisors for Surgery told me that taking time off from school raises "red flags". However people take time off for different reasons - failing courses, mental health resons, drug/alcohol problems, anger problems, travelling and research just to name a few.
The main thing all the profs tell me is that you have to be able to justify your time away from school and make it productive. Taking time off travelling by going to a beach and surf/smoke pot because you wanted a break does not go too well on the application packet, but if you spin it to say "I traveled and took time off during my medical school to underserved parts of the country/world and did something for the greater good and gain perspective of medicine/life/myself" is wonderful thing to put on your application.
You also have to weigh in the fact that most competitive residency are sadly more conservative. So you might not score big points for doing such positive things because it won't lable you as a research academic physician, but you will still stand out more than the rest of the candidates. Most interviews are bland unless you have something unique, and a good personal experience during medical school that changed your perspective is a good story.
I don't know exactly what you plan on doing, but we can talk about it more if you give me more details. I personally went to africa to do some tropical medicine research for 3 months, visited my family overseas, then came back to did a little surgery project with a surg prof of my medical school.
I guess the main thing is to be productive while you are taking time off. Have something to show for it when you apply for residency.
good luck