America is really the last hope out there honestly.
China is the obvious choice. However, the language barrier is a hurdle. Learning Chinese isn't like learning English or Spanish.
A lot of people aren't capable of tonal languages because they don't have a good sense of pitch and would be cooked. Their ears would physically hold them back.
Mexico been coming up a lot with more and more Americans moving there, but it's largely a mountainous country and the cities along the coasts would be insanely crowded. Switzerland also would be great, but small country geographically (again with an enormous mountain range) and people moving in would basically kills it's simple lifestyle, plus it basically has zero chance to survive a war based on where it is on the map and it's non-existent military.