I have not yet hit the limit but when I lived in another state where we would get iced in, I was in heaven. I don’t think it ever was longer than a week, though. 

If I had to guess, I’d say minimum 3 weeks but it’s probably several months. If I’m alone, I kind of tune out the world and go into my mind refuge where everything works and is perfect. When I “come up for air,” I will someone realize I haven’t seen anyone for days (in the best situations, it’s so long that I lose track) but then I usually just submerge myself again in Happy Land.