I also avoid US like a plague, but there are more options - in addition to Canada, one can also do Mexico or Panama which both count as North America. I was very impressed with Panama City when I visited in January, and it's a convenient gateway to Latin America and Carribbean.

Wanting to visit Australia is obviously a must for the challenge to work. I've been torn between wanting to try it at least once and being put off by the very unfriendly image their immigration authorities have. This challenge had a potential to break me to do it, but not with the new rules