You don't. Gentrifying a place pretty inherently means removing at least some of the people who live there. Why would the people of a small town go for that? Unless you're planning on subsidising the existing residents' lives forever as rent goes up.
If you have the money and influence to "gentrify" somewhere... just build a new planned community in the middle of nowhere. The US has plenty of nowhere.
If you have the money and influence to "gentrify" somewhere... just build a new planned community in the middle of nowhere. The US has plenty of nowhere.