Attaching a step ladder without a factory mounted rv ladder

My last rig had a ladder, and I used it. My current one does not have a ladder, even though it is a 'walkable' roof. I'm just no longer nimble enough to use the straight-up position of the factory ladder. However, I do have a little-giant ladder that works quite well and is much safer for me. When collapsed it is very manageable and goes in the back of my TV each trip.