Opening attic access into addition (like a dormer)

I don't know how else to explain this, so I took some pics..

I have a fully accessable attic except for one room that was added onto the house. I want to add some overhead lighting in this room and maybe blow in some insulation..

I'm thinking can I just cut away the roof decking between two trusses a bit to create access into that other room? (I realize I'll have to stay really low)

I don't know how those types of additions are built. Perhaps there's too much structural bits on the other side of the original roof deck.


Here's the outside roof of the room in question:


And here is is from the attic side:

 

I imagine it was built using either 2x6 or even 2x4 lumber as rafters and joists, so take the total height from the edge of the gutter to the ridge, and subtract a foot from it, that's what you would have left to skinny into. Highly unlikely it would be very navigable. I understand what you want to do, and you probably have the best solution. Cut the hole where you want to install a skylight, shoot some insulation in the attic, build the frame for the skylight and install it.

 

Actually when I say overhead lighting, I'd be happy with some track lighting.

I guess that's just that much easier. It'd be nice to be able to crawl in to lay in fiberglass, but I'd settle for a 16x16 hole to reach in for my wiring and to blow some loose fill insulation in.

Any reason you could think of why cutting the roof decking would be a bad idea?

I just have to make absolute sure to measure multiple times before cutting. I don't want to cut and then see daylight. LOL