I posted the link to the other thread, then read it afterwards, and realized that you had posted in it. Oh well, gives a link for others to read.
As for the time inbetween courses, all you can do is keep your fingers crossed that you might be close to home during the time or part of it. I notice that your profile says you are in NS. There is always a chance that you might get Shearwater or Greenwood for your pre-course time. As for your time in Cornwall, it will fly by. You will be so busy with the course that you won't have much time to think about anything else. And who knows, your course might be scheduled in such a way that you will be on XMas or Summer block leave and get some time at home then.
As you said, you never know what will happen or when it will happen. Think of the worst case scenario (most time away and far away from home) and if that's what you get, then you are already mentally prepared. Anything else, and you can take it as a bonus. One other thing, in regards to time away from home: if you end up going Weapons, you then have a course in North Bay to do. You won't find out until the end of that course (I think it is 4-5 months long) where you will be posted to.