That's understandable to want to structure your life. Heck, that is what I went through for four years, never knowing if I could sign up for summer recreational activities due to contracts.
If I were you, I would limit my contact with the employer to two calls. One during the application process, so that you can tailor your cover letter to the resume. That is the time to ask one or two short but pertinent questions, and this shows that you are savvy and a keener. (It will also allow you to say, "Our earlier phone call really showed that this position would be a great fit," or something like that). That phone call might even indicate to you, "this company is not such a great fit right now, so I shouldn't apply!" The other a follow a week later to indicate your interest in the position.
That is just my opinion.
Tina
(P.S.) my longest hiring period for me as a job candidate was when applying to work at the Government of Canada. Eight months after it was posted, I had to pass a written test. Then do an interview. Then have each of my references screened, all of which took 45 minutes each. Then, a year after the initial posting, the job got canned! So I was back to square one.