Don't rely on the president to win you the race. You can have the president help you. Use the popularity that he has. That may get you an ear into some of these voters, but he isn't going to close the deal.
As for whether what happened in Britain improves[Donald] Trump's chances of winning, I don't think so. He has the same chances; we may just be more aware of what they are now.
Assuming he wins his primary easily, and continues to push back when Donald Trump goes over the line, I think Paul Ryan is well positioned to run in 2020 if Trump loses.
Georgia has been on the fringes of competitive for a while now because of its black population and growing Hispanic community. The white vote is aligning more and more with Republicans, however, which has made it hard for Democrats to win. But, Donald Trump is not someone who sells well to suburban Atlanta whites, giving Hillary Clinton an in there.