Is it light or dark paneling? We had "pickled gray" in our bedroom here, but when we were taking it down so we could rerun some wiring (we were going to put it back up and paint it) we found mold behind it from water leakage. So we did the "plywood paneling" thing instead, and painted that white. I think the lighter paneling could support beiges and lighter earthy tones where the darker would be more chocolates and deeper colors. Our neighbor's house has REALLY dark walnut like faux paneling, and I can't imagine many lighter colors would compliment it at all. Their place is pure 1970's so everything is oranges and browns with it now. Personally though, if it was a rental I was looking to get tenants for, I'd paint the paneling to give the place a more updated and fresh feeling. Most people equate the sheet paneling to old and dated and worn, and it might effect the rent you can get, or maybe just the tenant base.

If "ranch trim" is really short with just a radius edge, then it's what we have in our living room, hallway, and a couple bedrooms. It's maybe 2" tall. It looks much better to paint that trim the wall color, which then means paint anything on the wall the wall color. Also, I wouldn't worry about trying to keep them consistent from room to room. The goal would be to paint them -- in each room -- in whatever way would help to camouflage them best.

What color are your walls now? Are you looking for something lighter? What about painting the walls the same Softer Tan? Hard to tell for sure, but this photo seems to show the same color for the walls and trim: https://www.decorpad.com/photo.htm?photoId=92215

I would paint it the ceiling color. But why don't you buy a it of poster board. Cut it to fit a small portion of it to fit into the squiggly space. paint one side the ceiling and the other the wall. Then you can test without painting wall. But personally, I would highlight it because its such a special feature and it will actually draw the eye up and make the ceilings look taller, in my opinion. Good luck!