Basic construction is from cardboard packaging insert. Walls from medicine boxes and styrene. Floor grating from needlepoint grids. Many odds, ends and recycled bits.
In the opening of Season 2 of Joe's Cantina, Percy's quarters are where we first learn that Lance Sputnik has had a... "malfunction." The cabin has so far played a small role in the story, but I put significant time into rendering the details.
For one, it's the part of the ship to have an "exterior" shot. Also there is a hidden storage spot in the floor which hasn't been seen in-story yet. But I have plans for that too. The main thing for me in building this set is that filled a need I had for some reason. When I world build around certain characters, it's comforting for some reason to see where the characters live, eat, breathe and sleep.
I remember Cap talking about having scenes set up for no purpose but his own entertainment, letting a story unfold as characters move around the set. That's kind of what I do here, as even when the main ship is put away, Percy and his cabin stay on the shelf, always in reach.