By virtually everyone’s definition Trump is a Populist. His policy ideas are a mix of big gov and small gov, of checks and balances and a strong executive.
On some issues he is conservative. On others not. On many issues he is flexible.
In some ways, picking a philosophy for America is like picking a business. It's not really so much his job to pick a particular business as much as it is his job to make a business friendly environment in America. It is then up to the business to compete and grow. In the same way, I think that Trump will create a conservative friendly environment in America. Political correctness is like onerous business regulations. If Trump can get some of the repressive crap off of peoples backs, conservatism will be given a chance to thrive. We still have to compete to grow, but at least the PC muzzle will be off. After that it's up to us.