Well, to see MK, you'd have to stay in the Tower. Are you booked in the Tower or one of the wings?
If you are booked in the Tower, all you have to do is request it when you make the reservation. Say "I'd like a Magic Kingdom view, if possible". They'll make a note of it but they do NOT guarantee it. They will, however, try to accommodate you.
I stayed in the Tower 2 years ago and that was my only request and I was lucky enough to get it.
It's really not possible to get a good view of MK in the Wings. You can sometimes see the fireworks but I don't think you can see the Castle.