We're going to install black blinds in our bedroom one of these days. The up/down pleated blinds just don't cut it for room darkening. We also have an outside door in our bedroom and it has no covering over the glass so when the sun comes up, it can be like a searchlight in our eyes. The only problem with the door is how to mount it and what to do for a valence. Installed a black Maxxis vent cover for the bedroom fan which helps a lot.
Here is one source of mini blinds for RVs that has some options for darkening:
Jacqueline Mosely blindsTry this one too. They have a thin 1/2" micro blind that is thin enough to also fit between a screen door and the the door glass.
Justblinds.comUntil I get around to installing new blinds, I've been using pieces of cardboard over the windows that I scored from the cg dumpster. Night and day difference.... ;)