Advice on (collaborative) work habits during isolating 'advanced' status, field work, or 'write up' stages?

To follow-up, here's what I would say:

1) In regards to sanity, I find that I need lots of social contact to keep myself from going stir-crazy.  Toward that goal, I just always network like crazy when I get to a new place (which has been surprisingly often).  I try to find friends in a nearby educaitonal instiution, or who are in academia more generally, or who are just in some kind of interest area of mine (board games, professional organizations, fun organziations) and then I follow-up on any opportunities for hanging out.  I try to avoid being annoying, but I am also quick to take up any opportuniy to hang out with people.  For me, its almost like ethnography -- the more people see your face, the more they sub-consciously start to think of you as a member of their community.

2) Toward the goal of an office, that is a good way to keep in touch with people.  There's just something nice about working side-by-side with other people doing work.  Here's what I've done in my crazy travels:  I became a visiting scholar at the University of Michigan, and worked in the computer lab until I got a job there, and then I worked in the shared workspace for that project.  In Atlanta, I worked in an empty office at my uncle's business, which was cool.  When I wasn't close to that location, I approached a satelite campus of Georgia State University, and the admin there was super cool and got me an email and internet account, even though I had no real connection to the univeristy at all (people are quick to help a mobile dissertation student for some reason).  When that ran out, I worked at the local library (always a good stopgap), then when I moved to DC I worked at a research space given to me by the Bureau of Labor Statistics.  Needless to say, somehow I've always scrapped something together, and I would just suggest asking any institution or friends nearby, because there is a shocking amount of empty office space, and also people willing to put a warm body in that space to make it look like it's being used.  Worse case, in Atlanta, they have these shared rent-by-the-use offices that are a new concept.  A lot of tech startups use them.  Google to see if they are in your area if that's what you can find.

3) Side gigs are a double-edged sword.  The right one will up your productivity by putting you in touch with a set of fellow workers, by offering you a workspace, and by structuring your time a bit.  The wrong one will take you down a road that's completely unproductive for your resume/C.V. and that steals time from what you should be doing.  It wouldn't take a part-time barista job, for instance.  Teaching is also pretty time consuming.  On the other hand, my job at Michigan has been an awesome source of funding with flexible hours, and having a job at an institution instantly makes you a credible member of that community.  "Why are you always at events again, Jeff?  Do you go here now? -- No, I work for Professor so-and-so -- Oh, totally cool then, you're obviously one of us, here are more resources for you!"

I wanted to draw attention this older post on maintaining your off-campus work ethic. I think the answers to the post offer analogous benefits to scholars in 'isolating' advanced status as (the original post's audience) off-campus work.

Thanks to Jeff and Brian for these answers. I really appreciate the advice with regards to office space,  visiting scholar status, and side-gigs. I have to say I haven't had the same luck with gaining formal visiting scholar status or any office-space perks at other institutions here in New York despite good and supportive contacts at major local institutions - though this could be a problem relatively unique to the realities of Manhattan real estate. But you're right about the amount of under-utilized office space more generally even here - at least in Brooklyn.

For one thing, there are semi-formal "co-working" or collaborative office rental arrangements (as you mention in Atlanta Jeff) that I've found to be available on a larger scale than one might imagine.  I've visited a couple, ranging in price from $100/mo for 3-days-a-week at the cheapest to more like $400+/mo for 5-days-a-week on the high end. Some - such as the Metropolitan Exchange - are really impressive, dynamic, and appealing spaces to work. I'm just not sure I can justify paying much at the moment without much income to speak of currently coming out of it. 

Moreover though, since beginning to cast about with a 'woe is me' plea for social contact and co-working possibilities among friends, I've actually found that those in decision-making positions over local small business office spaces are quite willing to open their doors as well. Several have confided that in fact they have more space than they can currently use, but don't want downsize (having in most cases only recently expanded) or lose their current space; they've been more than happy to have me occupy a corner for little or nothing in return.

Finally, I've been more 'direct' in my conversations with fellow academics here about my interest in simply meeting to get work done in each others company (and keep each other on task) at coffee shops and libraries. Nothing new about this, it's exactly what I'd be doing if I was still closer to my home institution, and it works too.

I've begun going to the office of a friend's start-up a few days a week, where I find a bustling and motivating (if still relaxed, social, and friendly) work environment quite conducive to productive days that also leave me feeling socially sated. A combination of a few days a week of this with a bit of my usual grad-student visits to cafes, libraries, workshops and talks (and yes daytime errand running) so far seems to be a big step in the right direction.