Hi Kristin! Thank you so much for sending in such a great question. It sounds like you have an incredible Walt Disney World Resort vacation on the horizon, and staying at 
Disney’s Polynesian Village Resort makes it even more special! I completely understand wanting to make sure everything goes smoothly with your reservations, especially when you’ll be outside the United States when your booking window opens. The good news is that you don’t have to worry at all, since you can absolutely handle everything from abroad.
As someone who always books my own reservations from abroad (I live in Mexico!), I can assure you that you’ll be able to access the 
Walt Disney World Resort website from pretty much anywhere in the world. You can log into your My Disney Experience account as usual to make dining and Enchanted Extras Collection reservations. VIP Tours and Minnie Van airport transfers are a little different, since you'll need to call for these. But as long as you remember the US area code (+1), you're golden! 
If, for any reason, you happen to encounter an issue with the site, such as a page not loading or an error during checkout, my best recommendation would be to call the 
Walt Disney World Resort help center directly. A friendly Cast Member will be more than happy to help you with your reservations over the phone.
One important tip to keep in mind is the time difference! Dining reservations typically open each morning at 6 a.m. Eastern Standard Time (EST). Depending on where you’ll be in the world on January 5, that might mean setting an early alarm or staying up late to log in at the right moment. Converting the time beforehand will help you be ready to grab those hard-to-get reservations right as they become available.
Kristin, you’re already well on your way to a magical and well-planned trip. With your organization and a little pixie dust, your March vacation is going to be absolutely unforgettable! If you have any other questions, please don't hesitate to reach back out to us. We're always available and more than happy to help here at planDisney. Have a magical day, and Happy Halloween!
Warm hugs,
Ana Paula