This article on the 5 best retirement places outside of the usual choices, Arizona and Florida, might provide some tips for choosing a state where favorable conditions and low costs exist if people setting up new parishes or missions are flexible enough to be able to move.
Populous and busy Virginia ranks among the top 5.
Though South Dakota is numbered in this group, I can't imagine anyone choosing voluntarily to live in that intense Mid-West cold. Neither do I expect there are many Orthodox numbering among the population unless there are descendants of immigrants from Orthodox countries long ago. Even then, the population is quite low overall. Finding like-minded souls or potential parishioners would be a challenge therefore.
Utah is included, but I have heard the cost of living is very high there.