I like the idea of teaching abroad...now is the time in your life to have an adventure. What type of degree do you have? That can make a difference.
now is the time in your life (prior to significant others, mortgages and children) when you can take some chances and try some things out. Go out and experience the possibilities......It will help clarify what you want later.
any interest in outdoor conservation? This is a good organization:
Also....see if you can land a job with a cruise line company....you get work and travel.
Teaching English abroad is an incredible way to see parts of the world and make new friends. You could do this while you decide what you really want to do. Would also look good on a resume.
I think it is definitely a good idea to get certified, but I don't know what the opportunities are like if you don't.
I had a friend that went to Japan. She ended up living there. I researched it 2 years ago. Unfortunately circumstances made it impossible for me.