Not an American, but the last time I rocked up to a random small American town and chose a random small restaurant, I had a really good turkey chili burger [1]. Hardly gourmet, but delicious, and it's quite difficult to find this kind of thing outside the US.
[1] The "Chili Monster" at the Dillinger in Boulder City, NV, in case you were wondering. https://www.thedillinger.com/ (Not to be confused with Boulder, CO.)
You can get top-quality Japanese food in thousands of small Japanese towns, and top-quality Thai food in thousands of small Thai towns. However, rest assured you will have a very hard time finding (say) Mexican in either. The only places in either country where you have a genuinely cosmopolitan food scene are Tokyo and Bangkok respectively.
[1] The "Chili Monster" at the Dillinger in Boulder City, NV, in case you were wondering. https://www.thedillinger.com/ (Not to be confused with Boulder, CO.)