Originally Posted by Johnny M
This is what I had in mind, this only illustrates the bottom or base frame of the cabinet.
Do you know what a stress skin panel is? A hollow core door is an example of a light weight
stress skin panel. The sum of the strength of the whole is much greater than the small, lightweight individual pieces add up to because you completely bond the surfaces together with adhesive.
Build the lower base frame on your workbench. Use cardboard as a template for the curved area and a jig saw to cut those curves. Then glue 1/8" or 1/4" light weight
plywood to one side of that wood frame and use a flush trimming bit in a router to trim it to the same size as your wood frame. If you wish to you can also put a layer of plywood on the underside and even have recessed LED lights
shining down from under the cabinet. The front face frame is built in much the same way and assembled on your work bench.you can attach it to the base before you install the cabinet. You can attach your cabinet in place by adhering some wood blocking directly to the shell. You don't need a ton of blocking, just place it strategically. You won't need any fiberglass tabs, an appropriate construction adhesive or thickened epoxy will be sufficient to adhere the blocking to the shell.
The way you are planning to do it is a lot more messy and time consuming and more difficult to get all the pieces to line up perfectly. Factories pre fabricate everything they can outside of the trailers and then install the pieces in place. They do not stick build piece by piece inside of the trailer. While I did not build trailers in a factory I was a professional assembler and fabricator of large commercial aircraft for many years and among the various jobs I did during those years I did interior installations including overhead cabinets as well as some cabinet fabrication work. So 95 % of the work should occur on your workbench and the other 5% is actually installing the cabinet.