I don't know about the other states but Cruz has a solid presence in PA. He was able to walk away with a huge win in the Pennsylvania Leadership Conference straw poll.
RCP Average 3/29 - 4/7 -- -- 42.8 27.0 24.0 Trump +15.8
FOX News 4/4 - 4/7 802 LV 3.5 48 20 22 Trump +26
Morning Call 4/1 - 4/6 360 LV 6.0 37 29 28 Trump +8
Quinnipiac 3/30 - 4/4 578 LV 4.1 39 30 24 Trump +9
CBS News/YouGov 3/29 - 4/1 729 LV 5.0 47 29 22 Trump +18
I'll be rather blunt, that's a genuinely stupid question. Have any of these states held their Primary elections while no one was looking? We are not going to know until Tuesday at the earliest.
You are saying Cruz has a ground game in PA, yet he has no shot at winning.
Trump has apparently done nothing in CA, yet here is the polling data from CA.
RCP Average 3/6 - 4/4 -- -- 38.3 31.5 15.8 Trump +6.8
Field 3/24 - 4/4 558 LV 4.0 39 32 18 Trump +7
SurveyUSA 3/30 - 4/3 356 LV 5.3 40 32 17 Trump +8
LA Times 3/16 - 3/23 LV -- 36 35 14 Trump +1
PPIC 3/6 - 3/15 321 LV 7.3 38 27 14 Trump +11
All we can go on at this point are polls, and it seems Cruz, who I like a lot, and Kasich, who is a Democrat, are wasting money in some states at this point.
So long as a brokered convention comes down to only Cruz and Trump being eligible to win, as per The Romney Rule of 2012, I'm fine with either in the general. Kasich I'll vote for but millions more like me simply won't. The GOP voters are telling him to quit, and his only win was in his open primary home state where he courted Democrat voters.