Insulating walls of balloon frame house
I think my house has balloon framing. Someone told me it's likely that the framing is continuous from the basement to the attic. When I'm in the attic, I can look along the sides of the attic down into what looks like the walls below. It's hard to see how deep it goes, because it's dark and kind of hard to look down into, because it's right up against the outside wall. The house was built in the 1880's.
Anyway, I was going to blow some cellulose insulation into my attic. However, I'm wondering if it's possible to blow cellulose into my walls through this access in the attic. I've heard that wall insulation isn't really a DIY project, and I'm not an expert.
Does it sound likely that this opening in the attic leads to the walls in the house? Is blowing the cellulose in this way a good idea, or would it just be wasting money on a poorly done project, since it might miss a lot of areas? Right now, my house has no attic insulation, and only a 1/2" backer board behind the vinyl siding for wall insulation.