I'm not advocating it-just that it is likely more closely to my own. I have seen this "sub-nation" type of model used to espouse decent opinions, and is pretty close to mine on the surface at least. I did not fact check it, or look at every reference, but it intuitively makes sense based upon my experiences.
I will look yours over as well. It always seems too "easy" to say rural vs urban, when my experience is, there are folks on both sides, in both places.
It does seem cultural to me. Just sayin'.
I think it is a mix, especially because we are dealing with blunt tools. For example, in my area, Missoula is the most urban and the most liberal, but according to census data, it is not urban, because its pop density is 2200/sqm while urban starts at 2500/sqm. But clearly for where it is, it is super urban, as the overall population density of Montana is about 7/sqm. So I think definitions become difficult.
I also definitely agree that there are large cultural issues at hand as well. Even in conservative areas, the mountain west and south are very different. I'd propose that there are cultural issues with an urban/rural overlay. That in any cultural area, the urban centers, judged by character as much as actual pop density, are going to be more blue than the rural areas, but that doesn't mean that an urban area in a culturally blue area necessarily is more blue than a rural area in a culturally red area. If that makes any sense. But I also do believe we are starting to balkanize more and more geographically. At least I hope we are.
ETA: I will say, from a back of the envelope calculation, the highest pop density counties Wyoming were D+7 compared to the state, Utah D+16, Montana D-4 (but Billings is a gas town and the next two were D+20), Idaho D+13, Colorado D+24, South Dakota D+8 and North Dakota D+15. Those are just near me, but it is in a very red area, minus Colorado.
Also, the urban areas in the culturally blue areas are both the densest and bluest, while the reddest are the rural areas in the reddest zones, which contribute almost no votes at all.