Re: Chapter 1: A Great Upheaval
It is an interesting question, because on the one hand, the book says that you can jump a certain amount and reach a certain height, then I think says that if you go beyond that, you might have to roll a Strength (Athletics) check. So, it seems, like RAW, you should be able to start climbing ladders by jumping.
But another thing to consider is that climbing a ladder already assumes you height to be where your feet are not where your hands are reaching. So, for Rose, with a running jump, she could get her feet 6' above the ground on a vertical jump. Jumping movement counts as regular movement, so jumping 6' will save 3' of movement over normal climb. I think that is all you could hope for without any special checks.
I think this jives with real life. Maybe you could save a fraction of time jumping on to a ladder, but it is probably not worth the chance of slipping of falling.