The thing is, people shouldn't change their vote just because they don't think their candidate has a chance. With this mindset, any third candidate never has a chance. This is ridiculous because people are then voting on who they hate the least instead of who they like the best. That's why only the hyped up candidates win. People just need to change their state of mind and vote for who they want. If everyone thought this way, we might get a better president...
And on the priority list of candidates you suggested... That would just be a more complicated way of recalculating the vote over and over again... It doesn't really make sense... Maybe a better way would to be to have several rounds, and eliminate the candidate with the least amount of votes every round... That still though sounds like a more complicated way to get just about the same results...
For me, as an outsider, the US president election is a quite much of a farce. The entertainment level is certainly bigger than for the Russian election, where it's blatantly obvious that the election is rigged, but anyway ... those claiming the US is the worlds biggest democracy they haven't read up what "democracy" actually means.
I believe tactical voting is a problem that can't be solved merely by insisting that people should vote for the candidate they believe is the best. I heard it before and just checked it up again at Wikipedia - it actually says that "(...) Arrow's impossibility theorem and Gibbard–Satterthwaite theorem prove that any useful single-winner voting system based on preference ranking is prone to some kind of manipulation", meaning all voting systems are prone to tactical voting - but some is worse than others, and I strongly believe the US system in itself excludes the possibility of a third candidate getting significant amount of votes. People being in favor of the third candidate pretty much has to vote tactically, or their vote for sure will be worthless.
I mentioned two alternatives - two-round systems are used in quite many presidental elections world-wide (including Russia - theoretically), as well as more local elections. Instant run-off is also popular, used in Australia and many other places.
Condorcet methods can also be either instant, with the voters ranking the candidates on one voting slip, or done as several voting rounds - the algorithms are supposedly better at finding a "compromise candidate" than the runoff-voting, but still there is room for tactical voting.