The way things are going for Hillary, she will be more concerned with the possibility of serving a term in a federal pen instead of serving as POTUS.
As for Trump, for me it depends on who ultimately wins the Repub nomination. I am a conservative, not a Republican. And, if another lame candidate (meaning moderate & weak) gets the nomination (as Dole, McCain & Romney did), I will see no difference between them and the Demo candidate. A weak, moderate Repub is essentially a lighter version of a Democrat -- and we all see where that has gotten us.
So yes, for the first time i WOULD consider voting for Trump as a 3rd party candidate if another turd should get the Repub nomination.
Here is more food for thought -- at this point we cannot say that the Dems will not also face a 3rd party candidate if one of Hillary's competitors decides to make an independent run. Would be amazing to see a Dem, Repub AND two 3rd partly alternatives (one opposing each major candidate) this time around.