SO basically just cut the real large pool noodles slightly larger than the width between the RV and the slide and wedged them in as a rafter. The large ones are stiff enough to hold shape and not sag much.
As you see in the bottom pic basically no water and we had 14 hours of downpours last night...1.5" of rain. That would have collapsed my topper and I would have 5 gallons of water pooled up.
I used two leftover pieces for the end one but that never sags on the end..otherwise it is one piece across. I think I got two rafters out of one pool noodle.
I just used a broom handle to slide then down into place.