I have a convertable Step/Extension ladder which sears USED to sell. it's just exactly long enough to put me on the roof safely.. More in a bit on that.
THey also make Telescoping ladders.. The one I have is too short but it's useful for a ton of other stuff.
The Factory POS .. I reached out with ONE HAND and pulled it off the RV.. ONE HAND.. it is good for about 150 pounds not much more The Sears ladder is rated 250 tested to 500 and works well with my 300.
The safely part.. I'm a former ladder monkey (Worked as a Roofer for 7 years when I was younger and more foolish) and very used to climbing a ladder set up at the proper angle. (Proper angle. Tips of toes to feet of ladder. Reach out arm straight and about level and grab a rung. Heal of hand: too steep. Finger tips: Too shallow: Comfortable Grip: Proper angle)
Climbing a VERTICAL laddre like the Factor POS.. Much scarier Much Much Scarier.
Highest I've ever climbed on a Vertical ladder: 100' (antenna tower)
I'm acrophoboic (Fear of heights) TRUST I did... In my safety gear.