I have been thinking, does superman's world have to be like ours with same countries and such?does superman have to have an America to work?
The idea is simple. Mangaka usually create separate fantastical worlds for their characters to have adventures with their own culture, politics, geography, physical laws, economy.. Etc. For example, one piece, naruto.. Etc. So, if you are into this idea create your own world for superman to crash land to with words or atleast the gist of it.

If not, why do you think superman needs to hang on to the real world?i mean, smallville and Metropolis are both entirely fictional.
Or Do you prefere a combo like harry potter or percy Jackson or bleach where there is fantastical world on the flipside of the real world?