One thing the game here underplays is that a lot of those "uncommitted" delegates are the Pennsylvania delegates, and if Trump puts in even a little effort he should get a fair number of those (~20 out of 54 PA uncommitted delegates strikes me as reasonable...start out assuming ~30 and give Trump a 10 delegate organizational penalty).
I guess the point is that if he doesn't get to 1237 in pledged delegate the race goes past June 6, though it'll likely be a done deal if he's within 20 or so.
Pennsylvania is probably a crapshoot, but it's one in which Trump is disfavored for a variety of reasons. First of all, who's running for delegate? I'd expect 4 main camps: Generic Republicans who just want a ticket to Cleveland; Bush/Rubio/Other supporters; Cruz Supporters; Trump Supporters. Only one of those camps supports Trump, and it's likely to be less than a quarter of the delegates on the ballot. That, combined with the organizational problems of getting people to vote for your desired delegates (plus Cruz's better organization in general) leads me to believe that Trump probably won't pick up more than a handful of unbound delegates in PA even if he wins the state.
Here's my current working projection for the remaining contests, for the record. (This leaves out the uncommitteds, of which Trump will certainly get some).
Don't forget to handicap Trump a bit because some of his supporters running for delegate will probably have foreign last names, meaning Trump's supporters won't vote for them.
