I don't think a average size woman can dead lift 80 lbs with a rope up a ladder by herself. Strong male adult/teen under side pushing up the ladder and the average size woman pulling a rope on the roof sounds doable.
All kinds of rental lift equipment out here to make the job easier/safer. Or a neighbor with a tractor with a bucket that will level lift the A/C to a 11'-12' to the rear roof line.
Not all rv trailer roofs have the same load limits. Mine does but that don't mean all will.
Ladder load capacity will need to be enough to cover the persons weight plus the A/C weight on the ladder while he/she is pushing up.
