Revision is a bit of a nightmare

When I picked up "Bring Me Comfort" again, I was excited by the parts of the story I still liked and pretty disgusted by the parts I didn't. No surprise there. Then I started to make notes of subplots and character changes that I thought would really benefit the story and I was even more excited. But then the reality hit me: how to incorporate these changes into my already written material?You'd think it wouldn't be that hard but it is surprisingly difficult to cut large portions of writing and insert whole new scenes and/or characters. I now have three different files open in Word - the original manuscript, the revision in process and new scenes. Hope this is the best way to organize myself. I guess I'll find out soon enough!