We have the factory installed ladder. Wow - we really need it! If we have a good rain, John climbs up on the roof to sweep off the slides. John often climbs part way up the ladder to check the roof as part of breaking camp.
We also carry a telescoping ladder in the basement. It is a bit heavy but very compact and very, very sturdy when telescoped. Bought it at Lowes. It's a Werner 13' multi-purpose telescoping ladder. Holds 300 pounds. Can be configured in several ways including scaffold.
We have it stored on furniture sliders in the basement which makes it easy to pull out and push back in.
We need this one for putting on front windshield screens, some motorhome cleaning (windows, etc.) and hanging bird feeders!