Heh, I think that might be a universal problem. the easiest way on or off a roof is though a hole in the roof.. but then what do you do to cover that?

I know I have that problem, plus the fact that my workshop is on a four foot plinth of ground on three sides, so just getting level with the roof takes the longest ladder I've got. Hence, the easiest point of access is from the inside.

Hm, skylight on a hinge perhaps with yours?