I agree with David T re the Trillium
roof. When I need to do things on my Trillium
roof, I use a ladder and then reach.
On my Boler
17, because it is 8 feet wide, I can't reach the roof vents so I actually climb on the roof, but before I do this, I brace the roof with 2x2's wedged between pieces of plywood on the floor and ceiling.