Insulation was the easy bit! Be sure to check out post 2 (Flooring) and post 3 (Structure) as you will see the insulation that is under those two things. Basically when you are building you just want to be insulating as you go. I plan to travel in the winter so the more insulation I could put in and stop any little pockets of cold air coming in, or when it is hot out any heat coming in, the better.
The most important bit to insulating is the windows. I ended up putting a total of 4 layers of insulation on those. Having the 4 layers helped to give a flat surface to work with later as well. In the photo below you'll see the first layer, which is your thin reflective material. Super easy to use and was more to block the sun out.
Next I used a thick piece of foam (you can see this in the video a bit better how thick it is) to fit perfectly into the window. Because the windows are sort of rounded I then placed a piece of thinner foam glued to the top of it and slightly bigger to make a super tight fit. All of my windows that are covered up have this.
*** When glueing foam pieces together, make sure you use the special glue made for it. If not you will melt the foam and it just simply won't stick together. **
Next is the fun bit. Wrapping your whole van to look like a space ship. Make sure to get the special metal tape. It works like a dream. You really can't mess this up and I had fun working around every corner.
Use the weather striping around your doors to tuck it into as well. I found this to be a quick way to get everything to stay in place along with the tape ... lots and lots of tape.
All in all you only get one shot to insulate your van. So decide if it is something that is important to you. It is one way to make your van more seasonal and not just your summer camper.
*** Just note unless you have a heating source doing a full insulation might not be worth the effort as your van will drop to whatever temperature is outside. The goal if you have a heat source it to just keep as much of the heat in as possible and vice versa if you are cooling. ***