The Republican side of the Primaries has one value only - comedic theater and Trump is a master comic (as Obama showed at the White House Correspondents' dinner the night before he took down Osama bin Laden).
Put anything that breathes as the Democratic nominee and you have the next President. There is just no pathway for a Republican in the General Election. The Senate seats in play this time around is the flip side of the last mid-terms when more Democratic Senate seats were up fro grabs. This time it's the other way around - many more Republican seats are in play and in purple States that Obama carried in both elections.
This Tuesday's Republican Primaries are not winner take all so the delegates will be divided. If Trump gets most of these and Cruz can't carry his Texas State then it's Trump by a big margin. If Rubio, the establishment favorite and where the money is, can win tomorrow then its a race for delegates - even up to the convention.
Hillary will put Sanders in her rear-view mirror after tomorrow.