Trump. If he is getting 50% of the vote in NY and is 25-30% clear of the 2nd place candidate, he'll likely win every county.
Correct. The game is to keep Trump below 50% in a majority of the CD's, so Kasich or Cruz collectively siphon off say 20 delegates - one for each of the CD's where they keep Trump below 50%. Trump probably has quite a chunk of wasted votes in Western NY, and on Long Island, and about 15 of the CD's have almost no registered Pubs, so it's hard to predict what will happen there. I don't see Trump doing very well in Manhattan, or the more prosperous parts of Brooklyn, which is getting quite high income these days. Trump probably will get over 50% in my CD alas, but it might be close.