Like how far abroad? If you are thinking about working within the developed countries of Europe, Canada, etc....its as difficult to become licensed there as here - unless you work on a US base stationed abroad.
In third world countries, you can go with an organized "group" - Doctors Across Borders" for example & provide services within the scope of what the group is there for.
Otherwise - its tough. (I had a friend who grew up & went to school in S Africa & became licensed there - emigrated to Israel - had to provide documentation of schooling & take the boards there in Hebrew - both oral & written. She emigrated later to Canada & said that licensing process was pretty easy & now she is going thru her licesing process here - so far 2 years into it).