It partly depends on whether you want to understand pre-9/11 "reasonable" conservatism or the more recent Tea Party and Trump conservative populism.
Ayn Rand expresses the fairy tale version of romantic, rugged individualism, which is pretty important to understanding modern right-wing politics, especially in North America. I think the main idea conservatives take from her work, directly or indirectly, is that progress is driven by individual work and achievement, and that any kind of forced wealth re-distribution (through social programs, for example) is effectively theft, and therefore immoral.
The modern populist right-wing movement was originally driven and disseminated by right-wing talk radio hosts like Rush Limbaugh. So, listening to right-wing talk radio or podcasts is also a good window into the modern movement. It puts on full display the resentment felt by modern right-wingers.
If you would rather not experience right-wing media directly, but would rather read rational analysis about it, then one good choice is David Frumm. He is an old school Reagan/Bush conservative, and has lived through the transition of the Repubs to populism. He is very critical of Trumpism, like most people, but he comes from the perspective of a reasonable and well-informed conservative insider.
Fareed Zakaria has a new book called Age of Revolutions, which views modern conservative populism as a very significant political re-alignment with similarities to various revolutions of the past, both successful and unsuccessful. Fareed talks about the conditions that lead to populism. In that sense, he treats Trump's popularity as a symptom and outcome of specific underlying societal problems.