Look at Trump's campaign organization. He's got some serious players in the campaign, people who would not sign on if this was just a lark. This is not a clown operation. Already, every county in New Hampshire has an org chart.
I also think Trump has a teflon coating. He seems innoculated against the kind of gaffes that would cripple any other campaign. It's almost like people expect him to be outrageous and over-the-top. That's just Trump being Trump.
The conventional media have not figured out how to handle him. Those who aren't old enough to remember Reagan (most of them) have never seen anything like this before.
Hah that's certainly true. They've thrown almost their entire playbook at him and he doesn't respond like their usual targets. He fights back, dismisses them, and moves on. He doesn't apologize, quit, and slink away. THAT'S where most of his appeal is coming from right now I think.