u/Dirkgently29

We want to add a catio to our yard. Unfortunately, the only potential window is a 5’ casement window that leads out to a deck surrounding a hot tub, with flower box walls.

I am thinking we could build a tunnel from the window along the house to the deck wall, sacrifice the flower boxes on that side to become tunnel support, then an elevated tunnel down to a bigger structure about ten feet away from the deck (we still need access to the side of the house, so it may have to be a bridge).

I saw another poster get their casement screen replaced by plexiglass and a cat door, which I think is our best bet too. My spouse is an excellent woodworker, but I need to come up with a well thought-out plan. Does this all make sense, and is it doable?