You "could" find yourself (as many including the last bunch of non-rated guys did) having a "K Area" contract for 6mths in the Summer to complete your line training. (and a little bit more, particularly for rated guys just joining NAS)
It has also happened that some have been given a 2nd consecutive 6mth "K Area" contract, conveniently (for some parties) at another base.
Not totally impossible that a 3rd 6mth "K Area contract may be offered (bizarrely at yet another base)
Ask me if anymore "Core" positions are likely in the forseeable future, and I would have to ask you to think through the reasoning behind these machinations/base changes, and what they are intended to achieve.