Most likely, none. Possibly Virginia, Colorado, Nevada and New Hampshire. Rubio almost certainly would not have replicated Trump's success across the Midwest and PA.
People here are acting like Rubio would do better because he's a "moderate" but that is a dubious assertion. Rubio is a Koch brothers guy through and through on every economic issue. Trump held strong capitalist views as well, but he mixed in populism with a willingness to get the government more involved in infrastructure and protecting fighting outsourcing. Rubio supports an outright ban on abortion WITH NO EXCEPTIONS, a position that the overwhelming majority of Americans reject. Especially running against a woman, that would have been a recipe for disaster. According to every exit poll, Trump had his best performance among voters who listed immigration as their top concern. Rubio would not have gotten that. If anything, his gang of 8 amnesty bill (written in his first term after he swore he was against amnesty in 2010), would have dampened conservative and right wing populist turnout for him.
I think the most realistic Rubio vs Clinton race sees him winning all of the Romney states + Florida.
Rubio is certainly more conservative than Trump, no doubt. But likability matters, and he had it in spades. All the head-to-head polls showed Rubio beating Hillary. Rubio would have done better than Trump with latinos and college whites. Hillary lost because she could not turn out the Obama coalition. Trump received fewer votes in WI than Romney, fewer votes in MI and OH than Bush 04.
That would be true if we assume Rubio's likability wouldn't have taken a hit if he was the target of an all out media onslaught for months leading up to the general election. They were happy to give him favorable coverage when he was attacking Trump. It would not have lasted. Especially on social issues.
Rubio also loses his charm under pressure (ex: robotically repeating the same talking point three times when Christie attacked him in the debate before the NH primary). He's a very good speaker, but only when scripted. Perhaps that would have been enough against Clinton, who was also scripted, but it's hard for me to say the guy who only won one county in his home state's primary would be a slam dunk in the general, regardless of hypothetical polling.
