I need clarification from the PC police. It's wrong to call Barack Obama by his middle name Hussein. It's wrong to call Ted Cruz by his given first name Rafael. It's wrong to call Bobby Jindal and Nikki Haley by their real Indian names, because, you know, bigotry. But it's OK to call Donald Trump by his ancestral name Drumpf because bigotry against Germans is OK? Is that the official ruling?
If Trump somehow pulls off a major upset in Wisconsin tomorrow, he'll hit the 1,237 not because Wisconsin's delegate haul is critical, but because it is one of the cuckiest states in the country. It's heavily German, Canadian-nice, conventional and friendly, enjoys little racial diversity outside of Milwaukee, etc. If he wins Wisconsin there isn't a state left besides Nebraska that he'll be incapable of taking.
As mentioned, that would constitute a stunning win. Iowa and Kansas are heavily German, too, and Trump fared poorly in both. The German (and Scandinavian) states of Minnesota, Nebraska, Montana, and South Dakota were and are going to be bad for him. Indiana is doable, and of course he won the open primaries in Michigan and Illinois, so it's not as though Germans are allergic to him (he is at 40% in national Republican polls, after all). The West Coast is a tough call but I'd guess his relative performance will be best in California, middling in Oregon, and worst in Washington, and that he'll win California but lose the other two.
(Non-Mormon) English is much better--he won Nevada, New Hampshire, Vermont, Florida, and rather surprisingly lost Maine (although less than 2% of the eligible adult population voted in the Republican caucuses in that state--if it were an open primary Trump would've won it). Pennsylvania is an outlier if he wins, which I think he will, but I'm not confident he'd be able to without Kasich in. The rest of the English/Irish/Italian northeast will be easy.
Missouri provides a nice illustration. Without the Scots-Irish "American" southern counties, Trump would've forfeited the state.
Finally, it's rich because of how critical Trump has been of Germany's civilizational-threatening handling of the migrant crisis. There is no Drumpf in Germania anymore.
* Jews are a major exception to what should be thought of as a tendency rather than a rule.