Not much to show in the way of interim photos. We used 1/2" black iron pipe to deliver the propane from the tanks to the points-of-use. The pipe runs down the driver's side of the bus, between the 2 middle rub rails.

Why on the outside? Simplicity of design, ease of installation and inspection, and convenient location of shut-off valves. We used pipe hangers near the joints and every 2-3 feet in the middle of the longer pipe runs.

Detail of kitchen stove propane connection.
The black iron pipe transitions to a ball valve, then to the final appliance connector. The connector is a stainless-steel sheathed rubber hose purchased at the local RV supply place. Rated for indoor/outdoor use.

This layout leaves all joints exposed, and the connection to the appliance is continuous from the valve to the point-of-use. No hidden joints or valves to lose sleep over. And I would!

I'll whip up some sort of sheath to protect the hose as it passes through the bus wall.

The first step in installing the bathroom window. We purchased a marine window from the Fuller Brush company. The standard spigot length (the part of the window that extends through the wall) is 2.5", which is the exact thickness of our walls.

The marine window is different from the other Hehr windows we've installed in the following ways:
-The trim ring goes on the outside, instead of the inside.
-The spigot has a downward slope of 15º

I used the inside shape of the trim ring to trace the window shape onto the bus exterior, then used a jig saw to cut ONLY the outside wall (since the inside will be offset slightly). The insulation has been removed in this photo -- you see the back of the interior birch paneling.

I then placed the window in the opening (upside down) to trace the opening shape onto the back of the paneling. This way I could duplicate the slope from the outside, and get the vertical offset just right.

I drilled several reference holes from the outside...and then lined up the trim ring on the inside, and traced the shape.

After cutting the hole, the window is inserted from the inside. The edge of the spigot is flush with the outside wall of the bus.

View from the inside. Nice to have some light in the bathroom. :-)

I pre-drilled the trim ring for six screws and applied a bead of butyl caulk to the back before attaching.

A bead of butyl caulk is applied at the junction of the trim ring and spigot, and smoothed with a fingertip (which is washed up with mineral spirits). :-)

Inside view with the window open. Although it's barely discernable, there is a screen in the window. The window pane itself is made from 5/8" acrylic (crystal-clear with zero distortion). A neoprene o-ring in/on the window makes a secure seal.