At this stage of our development we treat the Americas as one destination. Our first forays into this region are mostly for cultural/travel photography, though we expect to add specific wildlife and landscape options before long.
Central and South America make convenient destinations from North America and offer photography with an exotic element. Flights are relatively short and cheap - with no significant time difference; paperwork is minimal and there's plenty of interest.
Those traveling from elsewhere might find the travel more onerous, but the experiences no less rewarding.