I wouldn't say that moving within the US is necessarily easy. But I do believe that it would be easier for most North Americans than moving to Asia or Central America. I've lived in Asia, and it was fun. But I never got close to assimilating. My social circle was almost entirely fellow ex-pats (really a small community within a big city). My friends were constantly moving away. I had ok language skills, but I occasionally had to rely on others to help me with issues where language was a barrier. You sometimes step into cultural no-nos without realizing it. And not everyone you encounter is glad to see a Yankee riding the subway. Was a wonderful experience, but I didn't want to make it a permanent move.
But I totally get how cultural differences can be an issue even within the US. When my wife and I spent a few months in Alabama, we felt welcome but there are obvious cultural differences. People there are into football, hunting, fishing -- things I'm not really passionate about. But there were also people into art, music, and theater. We may have had trouble finding our tribe had it been a longer term stay, but not impossible. And having said all that, it's still America. They have all the same stores and restaurants that you're used to. You can navigate daily life without trouble. And you can just go there, get an apartment, and boom you live there now. Pretty easy by comparison.