When I removed the water tank, pump, etc. I also discarded the exiting sink as it was quite a bit larger than we needed and more than a bit decrepit. After a couple of times out, we found that we really needed a sink.
I made one using the stainless steel lid from a non-working electric fry pan. Then we bought several basins for various used that would fit into the new sink.
When traveling the basins and a stainless steel tea kettle ride in the sink.
Our sound system consists of two JBL computer speaker sets, the $30 ones from WalMart, each with two small satellite speakers and a small subwoofer powered by the trailer's 12 volt battery
. One set is mounted under a cabinet that I added, and the other under the cabinet at the rear that I added also.
The audio inputs to these are wired together to a small plug that fits a pancake CD player, a short wave radio and a lap top computer. The best way we've found to keep the CD player, radio and lap top quarantined during travel is to place them under the pillows on the bed with a comforter tucked in nicely under the mattress.
Unfortunately in implementing my KISS philosophy I have torn these wooden cabinets out and am replacing them with large wire shelves from the closet section of Home Depot. I also plan to upgrade the sound system. Perhaps one from Bose or one of the 'knock-offs'. These wire shelves are not as pretty as the nice cabinets with hardwood framed doors that I had previous made. But they have a much larger capacity, air flows through them and it is much easier to locate and access whatever is on them.
The front one is done and we like it, so will get busy on the rear one soon. So far nothing has fallen out during travel, but if this becomes a problem it would be easy to tie things down using bungee cords of an appropriate length.