try this link
http://www.catholic.com/library/Rosary.asp

Towards the bottom is the part "Meditation the key" that may answer some of your questions. Apparently meditation is good -- you’re in conscious control. I can see where a self-induced trance would not be good -- that’s more like escaping reality. In meditation, you focus on the reality that is God. God is so "ever present" that if you don’t stop and think about Him, you can easily take things for granted.

Seek and ye shall find! Blessings to you!