My plan has always been to make some sort of window coverings for R.E.D.
During our first summer I tried using static cling window film (link here).
It worked great, offering privacy at night,
but we missed being able to see out the windows,
and removing and reapplying wasn’t practical.
Last year we felt no particular need for night-time privacy,
but the sun blazing through the cabin added so much heat
to our little abode.
We still plan on someday adding curtains
but as a temporary measure this year
to beat the heat so to speak
we bought some
Mylar Reflective Insulation,
a double-sided polyester and aluminum blanket
which reflects 97% of radiant heat.
It’s so effective that NASA uses it to shield the International Space Station
against thermal radiation of the sun.
It was easily cut with kitchen scissors,
and pressed into the several window alcoves,
it was really effective in cutting the blazing afternoon sun.