"I have an opportunity to work outside the country for two years, a role that would lead to significant advancement. How do I weigh the pros and cons of accepting, but uprooting my family?"
If you are being afforded this opportunity and can do it — take it! The business world is global. The best business leaders are going to have global experience. Some progressive organizations are now discounting employees for senior leadership positions until they have global experience. So, if you are interested in advancing your career to the c-suite level, this is a must.
When I was in a corporate role, I was asked to consider an assignment in Japan. Well, I have a special needs son and that just would not have worked for us. This is not just a "you” decision; this is a family decision. You and your spouse or mate really need to have a heart-to-heart talk. The last thing you want is to arrive overseas and one (or both) of you becomes depressed because you don’t like the ways things are shaking out.
Put together a realistic plan. For example, if needed, is your spouse willing to stay home for six months to get the kids situated into the new environment while you are off to work?
The pros, to me, outweigh the cons, if it works for your family. You and your family will be exposed to the rest of the world. This will give you all a competitive advantage in the way that you see and experience life. Granted, you will be farther away from your extended families, but there’s always Skype! Make sure you negotiate at least one paid trip per year back to the States for you and your family.
The one caution I would offer is to be very intentional about maintaining relationships across the waters. "Out of sight, out of mind” is not something that you want to be a part of your story. And don’t forget to market your achievements and your ability to add greater value to the organization.
If you take the opportunity, you need to knock it out of the park to demonstrate leadership capacity. Just as important as that, though, is ensuring that your sponsors are intact and advocating for you.