The 2016 GOP presidential candidates are a large group, and they all have different policies and ideas. I think Ronald Reagan would approve of some of the candidates but not others. I don't think he would approve of Donald Trump because his ideas don't line up well with Ronald Reagan's policies.
There is a difference between being a Republican, and being an arrogant, right-wing nut. The 2016 Republican Presidential candidates are unfortunately, the latter. Ronald Reagan would not have approved of the far-fetched and ridiculous ideas, beliefs and views that these candidates are presenting. I believe that Reagan would have been the most opposed to Donald Trump's views, as well as his general presentation as a presidential candidate.
The plethora of candidates in the republican party love to mention Ronald Reagan, but he would not recognize the party if he were alive today. Sure, he would be all about cutting taxes, but he was also a good enough leader to know that sometimes you have to compromise to get things done.
Although Ronald Reagan was a pretty progressive guy, he would be as shocked as the rest of us at the GOP's 2016 presidential candidates. Reagan was an old school gentleman that would not approve of a male candidate berating and sexually insulting a female candidate regardless of her party affiliation. I also think he would be disappointment by today's candidates who show diminished thinking when they insult the current president on the world stage by calling him "weak and feckless". They are all attempting to project strength while at the same time looking like complete buffoons. There is no dignity in the current candidates, who seem to find themselves competing with each other to see who can be the most insulting or degrading. The party is in a downward spiral.