This reminds me of an adventure my father's cats once had.  This was
back before I bought my house, and I was still living with my
parents.  My bedroom was in the attic, which had a fan but not air
conditioning.  The two cats found that my window screen wasn't
latched at the bottom, pushed it open, walked out onto the roof, and
went exploring.  We found out about this at supper time, when we
heard meowing and found both cats perched on the metal awning over
the side door, peering in at us through the kitchen window.  At the
time, we didn't have a ladder tall enough to reach to the roof eves,
so my father climbed up on a six-foot-tall step ladder and tried to
coax the cats to come to him.  They would let him stroke them, but
retreated every time he tried to pick them up.  Finally, he and I
held the ladder up to roof-level and persuaded one cat, then the
other, to step onto the ladder and be lifted down, ladder and all.  I
then installed a hook and eye to hold the screen shut.

Later on, my father bought a taller aluminum extension ladder.  He
left it leaning against the side of the house, and the cats soon
learned how to climb up and down it whenever they got the urge to go
roof-exploring.