Black out / Tints for rear windows.

[ghost123uk]

There are a couple of old threads on this, but they are likely out of date, so I'm starting a new one

Spring is just around the corner so my thoughts are moving towards the modest camping conversion I will be doing. No full on boot jumps, but a bed and cupboard, covered in thin black cord carpet, that I've got all ready 

So to the windows, thin black curtain would be cosy, but I'm not sure it can be fitted neatly and easily and without eating into the space available.

What alternatives do you know of ?

p.s. = I don't need or want full blackout or silver thermal type thingies.