Simple answer. Trump is a "Rockefeller Republican."
"They were usually fiscally moderate to center-right, socially moderate to center-left, and slightly hawkish on foreign policy, and were thus sometimes referred to as "liberal Republicans". Geographically, they were most concentrated on the East Coast, leading to the nickname "the Eastern Establishment" to describe them at the height of their power."
http://rationalwiki.org/wiki/Rockefeller_Republican
Does anything about that not exactly describe Trump?
Like most wealthy northeastern Republicans, Trump falls in a narrow political spectrum from Bloomberg on the left to Giuliani on the right. The only question is whether he is closer to Bloomberg or Giuliani.
If Trump is the nominee, I will hold my nose and vote against Hillary, just like I held my nose and voted against Obama in 2008 and 2012. I have no illusions, however, that Trump is conservative, any more than I had any delusions that McCain and Romney were conservatives.