Insulation question – GreenBuildingAdvisor

I have a situation where the new roof was  framed over the old roof. I’ll include a sketch. My question is, where the old roof meets the ceiling it gets very tight and I’m practically unable to insulate much, at least not without touching the underside of the old sheathing. What is the best way to insulate around the old roof? Just fill it up under the roof, not worrying about touching the underside of the sheathing, and also fill over the roof where insulation would have been had the old roof not been there? That’s my hunch…

should I be worried about mold if my blown in fiberglass  is coming into contact with the old roof?