I roll out of bed, put on comfy pants, and shamble over to my work/ gaming pc. When I get hungry I go cook something. When I need to think through a problem I go clean the house, do dishes, or lay back in a comfy chair and think. If I need to get something done around the house or run an errand, I just go do it. If I need a nap, I take one. I do try to get up at 8AM and stop at 4:30PM consistently (mostly to be available for calls), but sometimes I get carried away when no one is home and work into the night or through the weekend (guaranteed time with no interruptions).
I'm probably about 4 times more productive working from home than from our office. It's very relaxing, I get some cleaning done, and I don't feel a strong need for much of the rigid structure you've described.
Spot on about socializing though. I live near our office and if I didn't have the option to pop in for a less productive but more social day, I would have to find something to fill that gap.