We needed 5-ft with our first Class C. The RV ladders are too rough on the feet with their little round rungs. Tried a taller version of the folding one RoyB pictured but it had to be used open and wasn't very steady.
Ended up with a 5-ft aluminum stepladder, used closed, just rested against the edge of the bunk. With its rubber feet, and the carpeted RV floor, it always stayed steady. I thought of doing away with the back legs and bucket shelf, but why...? It worked fine as it was and gave me a ladder for other uses as well.
It was one-hand-light and didn't rattle when stored on the bed for travel. Very easy to lift up and out of the way when camped.