I wonder how anyone above a "certain age range" is going to safely get off an external ladder onto the roof of a Class C? And then even more tricky, how to safely get off the roof back onto the ladder .... especially a ladder that is merely leaning against the edge of the roof? I wouldn't even have tried to do this 10 years ago using the very stable 10 foot orchard step ladder I have at home!
Here's the times I've had to use our convenient and safe built-in ladder to get up on the roof while on RV trips - often out in very inconvenient places or situations:
1. Put Eternabond around the top edge of our front cabover window in a rainstorm to stop the leaking because the temporary new window was improperly installed by a glass shop 2500 miles from home.
2. Repair the front vent cover that was cracked and coming loose from wind pressure at road speeds out in the remote Oregon Outback.
3. In a parking lot a long way from home having to replace the sewer cap that a low hanging limb had knocked off.
I'm around 230 lbs. and the ladder on the back of our Winnebago Itasca Class C is rock solid after 11 years - held in place by 24 screws. I get up there quickly and safely many times when the RV is sitting in our back yard - often to wax the roof and do maintenace chores. i.e. I've had to replace the sun-cracked vent covers a few times over the years.