On the other side though I dunno what Cruz is doing lol. It's almost a sure thing Trump is going to win the numbers, and even if he doesn't reach the minimum required for the nomination and they go to the convention, Cruz surely isn't the one they'll pick either.
Everything hinges on a brokered convention, and part of that is based on how close Trump is when it happens.
If Trump is only like 100 away from the nomination, he'll probably get it anyway.
If Trump isn't that close, but Cruz is still lagging behind, then Kasich is their most likely choice.
Cruz's battle plan has to be "Keep Trump from getting any closer, but put up a good enough showing that I'm a credible candidate". This plan is foolishness for the reason you point out; he's loathed, and his path
always had to involve getting the nomination outright. The most he can do now is damage Trump and hope the ensuing chaos gets him some kind of advantage moving forward.
Truth be told though, none of this matters; just looking at the math, Trump will have the delegates by the convention, or he will be so close that brokering him out will cause the party to implode.