What is the endgame for sedevacantists? "Sedevacantism" is the belief that the See of Rome is currently vacant; that is, there is no current Pope.  There are not very many people who believe it, but they do seem to be pretty vocal on the Internet. One thing that I don't understand about it is: What do they think will or should happen in the future in order to resolve the situation? (Of course, the non-sedevacantist majority don't think there's a situation to be resolved at all.) The bulk of what I've read consists of their detailed complaints about recent Popes, along with some wrangling about election procedures and the like; but I haven't seen much that's about the future.

I understand that some of these groups have tried to elect their own Popes. Do they think that the global Church will/should come around to their position? Is there any kind of plan for how this might happen? Or are they content to remain as an elite minority while everybody else is condemned?

I ask partly because I have a sense that there is an eschatological dimension. The contemporary movement reminds me of the late mediaeval apocalyptic theory of an usurping pseudo-papal antichrist and his battle with the true Pope, this being one of the signs of the end of history. (See for example Bernard McGinn, Apocalypticism and Church Reform 1100-1500, in vol. 2 of The Encyclopedia of Apocalypticism, 2000.) I have seen sedevacantists talking about the so-called Prophecy of the Popes, which has quite an end-of-the-world flavour.
There are, unfortunately, numerous sedevacantist groups that disagree with each other. As indicated in the question, there are some that have tried to elect their own popes. There are also the Feeneyites, particularly associated with Most Holy Family Monastery, who deny the doctrines of baptism of desire (and, I believe, also of baptism of blood).  For another viewpoint, one with which I agree, I strongly recommend that you look at some of the material at the web site http://www.traditionalmass.org/ and particularly the link "Key Issues".  You might also listen to some of the sermons at http://www.traditionalcatholicsermons.org particularly those of Bishop Sanborn.  (You'll be able to tell from the titles which ones are relevant to your question about sedevacantism and which ones are general Catholic doctrine).

One example of how these groups could see the issue resolving is  Bishop Sanborn's position, which is essentially that the administrative structure of the Catholic Church continues, despite heresy, so that the modernist popes have valid elections (and the cardinals valid appointments) but are impeded from having the authority of the papacy by their lack of the Catholic faith. So the crisis would be ended if one of these popes were to abjure heresy and profess the Catholic faith (and, I suppose, receive ordination and episcopal consecration in traditional rites).