The press must treat Trump like a real candidate.
Use all the metrics, regardless of whether you feel his supporters will care. That's not even an interesting question, because until you report it, you can't know.
Over time the novelty of Trump will wear off. And people will be left with the reality of a loner, with no experience, trying to run a ridiculously huge and dangerous organization.
You have to give the electorate a chance to experience Trump as he is, with sobriety, and evaluate him not as a TV show, but as an administrator, leader, and military commander.
Trump is in every way a real candidate, and if elected will be a real President. Your job is to make the people feel that. If they still want to go with Trump, so be it.