First the Marine Corps hair regulations does not require you to have a high and tight. Personally I hated that cut and only had one while I was on the Drill Field at Parris Island. I went back to a high regulation shortly thereafter.
As far as what civilian attire to wear, it can be dictated by the culture you are in. Of course you probably already know that. But in some parts of the world, I found that if I wore a coat and tie, I blended in just fine....you will look like any other business man on travel, especially with a true regulation haircut.
Some how I lost this part when posting:
Otherwise I can concur with your thoughts….I can spot a Marine a mile away too…