Window insulation?

[SlowStig]

Hoiping this is the best section to put this, I am currently looking into options so I can sleep in the back of my offroader and so far have made a false floor which lifts the rear up so it is level with the rear seats folded down, giving a nice flat surface. I am just trying to figure out a way to mask the windows to insulated and give a bit of privacy.
I was thinking of making some insulation sandwiched between thin wood or cardboard, mounted to the windows with suckers or velcro at the top of the windows and bottom of the windows. Can anyone suggest anything better which wouldn't require being solidly mounted to the car(I am reluctant to screw anything into trim unless I have to)?

Is there anything else which others could suggest to look into? I have some other ideas to make it more comfortable such as making a small table, but as its something which I haven't done before I am not sure if there is better ways to do certain things?

[louiebaby]

Back in the day, we chopped up some insulated reflective sunscreens to the required size, then used a hole punch / metal ring inserter thing to make small holes in, which we could put rubber suction cups into.

Basically, these:

https://www.eurocarparts.com/ecp/p/car-accessories...

https://www.amazon.co.uk/20mm-Round-Button-Suction...

https://www.ebay.co.uk/itm/Rolson-Leather-Hole-Pun...

Sort of.

Hopefully you get the idea.

[LemonParty]

In my camper van, I have used the silver bubble insulation from B&Q, and used spray carpet adhesive to fix it to the lining carpet I used when I lined the van.

Cut them to the same shape and size of the windows, and tuck them in when you want the privacy / insulation. it helps that there is a lip all around the windows though, but you could always go with the sucker idea stuck through them.

[snowandrocks]

If you make up insulated shades or even just thick curtains, Velcro tape is more than strong enough and fairly unobtrusive if you pick tape in a similar colour to your interior trim.