In answer to your question on how I made the over the bed cabinet in my 179 as nearly as I can remember, I made it 2 ½ years ago, keeping in mind that I am not a carpenter and my terminology will be a stretch but here goes.  I wanted to keep the cabinet off and above the window valences.  With that in mind the finished bottom of the cabinet is 18.5 inches deep and the finished front of the cabinet is 12.75 inches tall.  I used a sheet of 3/16 plywood/bead board for the exterior of the front and bottom.  Using some scraps out the sheet of plywood I cut two end pieces for the cabinet that looked like a pregnant triangle to match the curvature of the front wall/ceiling of the trailer.  Once those end pieces were cut to the correct pattern I cut to fit 3 cross members for the cabinet skeleton out of pine 1x2s.  The end pieces were screwed into the cross members.  One cross member at the bottom back lays flat, the bottom front cross member was in the upright position when the end plates were screwed on and then the front top cross member was also in the upright position when the end plates were screwed on.  I then used more 1x2s as spanners between the bottom 2 cross members and the front 2 cross members (I think I used 5 spanners on the bottom and 4 spanners between the front cross members) After the assembling all these parts it’s installed in the trailer using screws in the end plates into the aluminum framing (about 6 to 8 screws running on the top edge of the end plates, then securing the bottom edge and front edge into the wall with screws and into the aluminum framing if possible.  Using long enough screws and if you can find the wood framing secure the top cross member and the lower back cross member into the wood framing behind the wall/ceiling of the trailer.  Once you have the skeleton of the cabinet installed you can install the exterior finishing (I chose bead board).  On the front of the cabinet using the spanners for the edge support of the door openings cut out the doors from the front skin and reuse these pieces after trimming them out to be the doors.   Paint; mount the finished doors with hinges, door supports, and door pulls as to your décor.   Install a false bottom on the inside of the cabinet of luan that you can run the lighting electrical wiring through from the ceiling light in the cabinet to the head of the bed for installation of a task reading light.   Wala you have a cloths storage cabinet.  The task lighting, hinges, door supports, and handles were purchased off Amazon.  The cabinet is doing what we had in mind for it and it seems to be holding up.  If need further information or have more questions you can PM me.  Hope this helps you.

Once we got the cabinet installed then we had to update the décor on the factory installed cabinet over the dining area, so we changed out the glass inserts in the cabinet doors with bead board and painted them all.  It never ends.