It seems that there is a lot of clever thought that goes into the design of an RV. Sure, some of it goes to save a few bucks, but much of it is about making the most of the available space. The space over the driver's cab is a bunk bed. The sofa isn't just a sofa, it's a hide-a-bed. Even the dining table can be converted into a bed. Many of us use the space below our bed at home to store things, but an RV makes that official. The space below the floor of the living area holds some of the equipment that doesn't need to be in the living area of course; like the water heater and the holding tanks. The rest of that space is referred to as the basement, and just like in any other home, it's where you store stuff. There's really a surprising amount of storage down there. Inside, there is an overhead wall cabinet just about anywhere you could possibly put one - not much space on the walls for hanging those photos of the kids and grandkids. (I suppose one would need to rethink how you hang a frame in a home that travels down the road.)
At first glance, it would appear that the RV's shower is open to the hallway. There is no door to separate the living space from the shower area. Haven't these RV designers ever heard of modesty? But there is something interesting about the tiny room where the lavatory and toilet are. Although the room is very small, its door is as big as you would see in a handicapped restroom. I wondered why. The first time I allowed the door to open wide, it made quite a clunk as it hit the wall on the other side of the hall. At first, I thought I had let it hit so hard that I broke something. Did I mention that the lavatory is right across from the shower? When you open the lavatory door just a bit beyond ninety degrees, a magnetic latch grabs it and holds it against the opposite wall. The door now serves as the barrier between the shower and the living space. Otherwise, you would have needed another pocket door and that would have wasted three or four inches of precious space. They even used a piano hinge on the lavatory door instead of the usual type hinges. This way, no matter what position the door is in - open, closed, or in between - you can't see through the crack between the door and the door's frame; thus ensuring privacy.
The popup we rented a while back had some pretty unique engineering in it. When it is traveling, it's only about three or four feet tall. So, the door that covers the entry in only three or so feet tall. How do you make a three foot door become six plus feet tall? The answer is that you don't. The travel mode door is latched fully open when the unit is popped up for use. Another door is velcroed into the door opening. That door is removed and suspended from the roof while traveling. The popup's kitchen cabinet is taller than the trailer is when traveling. So, it is actually sawed in half at about two and a half feet high. With hinges and flexible plumbing hoses, you fold the top half of the cabinet down into the floor in front of the cabinets bottom half. Pretty clever.
Most new RVs make use of slides. A slide, basically, is a moveable wall. The most common use is to provide additional space in the main living area; the wall that the dining table and sofa are set against slides out two or more feet when the unit is set up for camping. This provides a much bigger feel to the living area. When traveling, the slide is retracted into the unit. When in traveling mode, you can barely get between the couch and the kitchen counter. Some units will also have a slide in the bedroom. The more expensive units may even have two slides in the living area on opposite walls. This can make for quite a large living space in a vehicle that has to squeeze down to less than a 102 inch width while traveling.
Back to that skylight in the shower. The shower has to be built up on a platform that is several inches above the floor. This allows access below the shower should there ever be any problems with the plumbing. But since the shower is already in a part of the RV where the ceiling is a bit low, even only slightly above average height men would have to duck while in the shower. Skylight to the rescue. That raises the ceiling above the shower about five inches while also giving you something that is attractive. Win - win. Pretty clever..........Hardware