Well, there is that Starbucks...eh, not that appealing, and maybe not quiet. I do so people with laptops all the time.
Well, maybe we should see each other around more often!
So I was thinking about this problem of yours. Lack of socialization opportunities afforded by current employment has you missing your old digs. So, why did you switch jobs in the first place? Is that reason still valid?
Normally, and no one who posts here is in the middle of the bell curve, people begin missing the familiar when the shine on the opportunity they have switched into begins to fade. So what was the bright shiny thing that got you to switch gigs, and how far from reality is that bauble now?
One of the hardest thing for anyone to do is admit they misjudged an opportunity.

well, the shine is still on the actual job - it's much more fun and challenging. i don't have to supervise dolts. and the economic reward potential is fantastic! there was no way i was staying where i was, no matter how many buddies there were. it's really just quiet here, some joking but not a lot of just plain fun chatting.
Library, lots of people around but they won't talk much or bother you. Plus, lots of free magazines and papers. I'm writing from one now! I've been working at home and found it hard to tune out the distractions of the chores, TV, pets, roommates, but I'm getting better at it. I zone out with music or headphones, or my fan which makes enough white noise to block everything else out. I force myself to sit and work until a specified time. As for people interaction, getting out for a walk or gym visit is good for socializing and excercise. At least you don't work at night when everyone else is asleep and the gyms are closed. Lunch break eating out, hang out with some seniors or homemakers that stay in the neighborhood during the day. Course, significant other might not like that. I have some collegues/buddies that meet on Monday night for cheap beer and pizza and networking. When I was in school, people partied hard on the days off because they were so starved of socializing from 12 hour days of studying and classes. Course, kids seems to need less sleep than me...