Cruz does need to win Iowa in terms of momentum that will help him in New Hampshire, where a win will be tougher.
An Iowa win sets Ted up for South Carolina later in February and the southern states that follow March 1st and March 8th.
True, if Cruz wins Iowa, he can survive whatever oddball crap the little out of touch cross over electorate does in New Hampshire.....and go into SC with momentum. If Trump wins NH, which seems plausible, he will also go into SC with good momentum.
SC setting up to be crucial, as is usually the case.