smiler- I think it's a bad idea to get curtains...
I used to avoid the windows too... and mirrors... maybe what you could do is sit in your sunroom for a little bit every day... and look out the windows... just enjoy your home...
and gradually increase maybe 10 minutes to a half hour and then eventually sometimes sit in your sun room at night... and if you need to keep a knife close at hand so that the evil man doesn't jump and scream atcha... then do it to feel safe...
Maybe then you could actually stop for a moment when going through your sunroom at night... take a seat... maybe open a window and listen for a minute.. or however long you want...
What could make it easier is taking up a hobby to do while in the sunroom, to ease the anxiety about being seen.... like painting or crafting or building model cars while you sit in it... all are time consuming... and before you know it.. you may have spent hours in the sunroom.
As for me, I'm ESPECIALLY paranoid at night, and every sound sets off my panic.. well it used to... not so much anymore with my meds. I used to walk around the house peeking out every window with a baseball bat in hand looking for a mysterious lurker or something... but my dog helped with that... if she hears a noise she barks (if it's outside), and usually I'm hearing noises that are INSIDE the house... so that helped decrease it.
I hope in some way that this helps
(HUGS)
Twiggygal~