You actually say that a person "es de campo" or "es muy de campo" when that person lives in the countryside and is very attached to country life. You also say that a person "es de pueblo" when that person lives in a small town and you actually say that a person "es muy de pueblo" when that person is very rural. Those expressions are colloquial but quite neutral, they can have any positive or negative connotation you may want to attach them depending on the tone or the context. As for words with somewhat offensive connotations for a rural stereotype (like "yokel", "redneck" or "hillbilly" in English) we have words such as "paleto", "cateto" or "pueblerino" in Spain. In other Spanish speaking countries other words might be used. But you must consider that rural stereotypes are quite different in the USA and Spain, and even among Spanish speaking countries, so much that it almost seems like talking about completely different things. In Spain, there's the stereotypical paleto usually wears a "boina" (some kind of beret), so we even have the expression "de boina a rosca" (literally "wearing a screwed-on boina") or "paleto de boina a rosca" to refer to a very rural person. The expression is both offensive and humorous.

This can vary from country to country, other examples: Guajiro // Campesino // Campestre etc

Campesino