Waking up a few days with the van in middle of hopping neighborhoods while people are active just outside the van made privacy/black out shades our first order of business. We tested some reflective material, thinking it might help block the sun on hot days, but it was easily seen from the outside. Black made sure it simply looks like dark tint rather than someone trying to hide the fact they are inside.
Jen leapt in and took charge on this project and the result was some fantastically crafted, built-in insulated black out window coverings that we can easily store under the mattress (or in a custom cabinet later if we decide its needed), pull out when were about to boondock and rapidly convert into “stealth mode”.
These have a reflectix core thats embedded in a high strength fabric (that also happens to shed lint, or more importantly in our case...dog hair perfectly). The insulation should not only help us camping on hot/cold nights but also means they fit perfectly into each window without a lot of fussing with trying to straighten everything out. It's also keeps them from being a jumbled mess of fabric and magnets when stored, which we hated with our curtains in the bus. A few well placed rare earth magnets sewn onto the perimeter and these suck right into place against the window cavities as we setup camp for the night or within seconds of pulling into a parking space to enter "stealth mode" for the night.
So far these are working perfectly for us and I love the fact we didn't have to put extra holes in the van for snaps like some insulated shades sold online require.