Meanwhile, the nationalists tend to do better in Siberia and other remote areas - basically the areas Yelstin won in 1996 and where Putin and Zhironovsky over-performed in 2012. I made a map of how the parties did in in 2012 relative to their national total a while back for a different thread:
United Russia
Communists
LDPR
Prokhorov
A Just Russia
Places where Putin over-performed are just the places where the largest vote fraud happened. But other parts of the map reflect actual voting patterns very well (e. g. most of the gray regions are indeed "liberal strongholds"). Maps for each candidate or maps like Zyuganov vs Zhirinovsky or Zyuganov vs Prokhorov would be also very interesting. Though I'd say that the most noticeable difference is not between remote and non-remote areas, but between North and South, and I would describe this split as a split between the "Red Belt" (South) and the non-communist North. Not just Zhirinovsky but also liberal candidates tend to over-perform in the North. But yes, it also seems like Zhirinovsky is particularly popular in Siberia and the Far East.
I think to lump, say, Zhirinovsky, Gamsakhurdia and Nazarbayev together because they all can be described as nationalists is like say there isn't much difference between Romney, Ron Paul and Trump because they are all Republicans. Even worse, since "nationalism" is an especially vague word. I suspect the first thing that comes to a mind of an average Russian when he thinks about Zhirinovsky is not that he is nationalist but his personal qualities: those who dislike him would say he is a dangerous psychopath or, at best, a clown, and many of his supporters are attracted mostly by his eccentricity and craziness (and he also believed to get a lot of protest votes). Many Russian nationalists also support him, of course (at least as a lesser evil in their eyes)... but many of them also support Zyuganov. Depending on how you define nationalism, it can turn out that Zyuganov and his average voter is more nationalist and more consistent in his nationalism than Zhirinosky and his average voter respectively.
This is probably especially true for 90s: early LDPR included quite a few people not known as nationalists at all but well known for their extravagant and eccentric behavior, e. g. Marychev and Mitrofanov.
Zhirinovsky was a kind of Russian Donald Trump (especially Trump at the early stages of his campaign when not everyone took him seriously; of course, if Zhirinovsky managed to pass in the second round and especially he would win elections, people will start to view him differently too). And Trump probably has a more coherent ideology, actually.
I tend to agree. Despite his seemingly extremist political positions, Zhirinovsky many times cooperated with government both under Yeltsin and under Putin. There is even a theory that he always was a Kremlin provocateur :-).
And Zyuganov's victory also could end up like Voronin's victory in Moldova: some changes would happen, but not radical. But nobody can be sure in anything.