The alternate choices you speak of are totally implausible for winning the Presidency at this point. The die has already been cast for this election cycle and thinking there is an alternate scenario is wishful thinking.
If you are really serious about an alternative to the 2 major parties, the time to do something about it is the day after the election. Find viable candidates for these new parties. Get people elected to lower offices to get a movement going. Get funding and support for the new parties so that when the election rolls around in 4 years there is something real there. Not some no name guy that we know nothing about and has no apparatus for success (McMuffin).
Implausible but not improbable based on our electoral history. (that would make an 8-12% chance depending on what election factors you look at). The biggest chance out of that is the 270 strategy I've discussed before and polls actually make it a reasonable possibility.
But even if it is totally implausible, that's just a choice we each have to make. Do what we believe is right or go along with the crowd because it is popular. Each person has to make that decision and stand on it, even if they stand alone.