Let me ask a question to the OP.

If it's an emergency and people are trying to reach you, do you really want them trying to figure out which international number to call you at?

For your trips, because of the length, I'd reccommend you simply turn on international roaming and be done with it. Yes, it's more expensive. But A) You have your US home number, so everyone who needs to knows where to reach you. and B) You have one bill for expenses.

It depends on how much you use the phone, really. If you can keep usage to under 5 to 10 minutes a day of talk time, there shouldn't be that many issues with cost.

Regards,
-Bouncer-