Kismine

Hey there! 
I just started classes this week and I can definitely say I've reframed my whole way of thinking. The whole being older thing seems to matter not one bit and I'm taking my boyfriend and daughter to a departmental BBQ this weekend. My cohort is very nice and supportive and we are all commuter students, so it seems that social outings will be well planned but worthwhile. Everyone knows I'm a parent and even though I'm the only one among the group it seems like it's no big deal. I'm very happy with the group I have. Given that we're all commuters I'm actually considering holding some sort of social event at my apartment now to get us all together. Long story short I worried quite a bit more than I should have :-)

Heh well then Europe seems like it's out! Looks like a partially or fully funded masters is the way to go if you don't get accepted to PhD programs this cycle. 
Absolutely agree with @Sigaba's suggestion to figure out what history means for you. I wouldn't be overly  worried, though, about the (admittedly touchy) subject of interdisciplinarity. Some programs (Cornell's, to take one example) actively encourage working with scholars outside the Department of History. Others are known for their strong departments in other social sciences, and are known for blurring disciplinary boundaries in innovative ways (anthropology at the University of Wisconsin-Madison and the University of Michigan Ann Arbor; sociology at the University of Chicago). Just be judicious in where you send your applications -- avoiding cranky cranks.   As for readings:   I'd start with the classics (outdated in some ways, but they'll give you lots to chew on): March Bloch, Apologie pour l'histoire ou métier d'historien, 1941 (trans., The Historian's Craft, 1953) R. G. Collingwood, The Idea of History, 1946 E. H. Carr, What is History?, 1961   Then some newer books/articles: Various books and articles by Reinhart Koselleck (many have been translated into English) François Hartog, Le Miroir d'Hérodote. Essai sur la représentation de l'autre, 1980 (trans., The Mirror of Herodotus: The Representation of the Other in the Writing of History, 1988) Michel-Rolph Trouillot, Silencing the Past: Power and the Production of History, 1995 William Cronon, "Why the Past Matters," 2000 François Hartog, Régimes d'historicité. Présentisme et expériences du temps, 2003 (trans., Regimes of Historicity: Presentism and Experiences of Time, 2015)   A couple textbook-like resources on historiography: Caroline Hoefferle, The Essential Historiography Reader, 2011 Eileen Ka-May Cheng, Historiography: An Introductory Guide, 2012   My absolute favorite is a book that hasn't been translated into English: Antoine Prost's Douze leçons sur l'histoire (1996, revised 2014). It's a wealth of resources on the practice of history, history's relationship to other disciplines, trends in Western historiography -- and it's written in an accessible, often droll style. If you get less terrible at reading in French, give it a try! I can't recommend it enough.    

I first heard that retirement story back in the early 80s, from a college president who would have known how things were looking.  Then, I suppose, faculty members forgot to retire just as humanities departments began shrinking and the PhD output exploded.  
The good part of this for undergrads is that there will be some excellent professors finding work at otherwise forgettable colleges and universities.  If that starts to pop the prestige bubble that drives college admissions (and tension levels among high-schoolers and their parents), that will all be positive.  But it is not a great time to be looking for work unless you're well-connected or in possession of some useful handle on your CV.

I keep everything. It's the archivist in me. 

Digital-- Yes. The other day I found an old paper from a class I took in my third year and oh my. OH MY. It was fun.

Don't count on it at all.  Universities are increasingly replacing those tenured positions with adjuncts to capitalize, I mean, exploit the labor force.  Little pay, no benefits.  Departments have to work hard to lobby for tenure-track positions and proposals are not always accepted (I've see a fair share of rejected hiring proposals).

I'm in a similar situation as you. I graduated December 2016 and will be going to grad school fall of 2018. One thing I've found wildly helpful is to keep a running list of articles, books, passages, etc. that are applicable to my desired research field. I just keep a spreadsheet on Google Sheets with the title, link, a short explanation and the date. For passages out of books that I want to be able to refer back to later, I have a running note on Evernote with all necessary biographical information.
I've also found a couple projects to work on to keep my writing sharp. I blog about every other week and while it doesn't have high readership (my mom likes it though ) it gives me space to craft an argument and present evidence like a mini research paper. And I can write about anything I want! Just remember that graduate schools are likely to do a social media check so keep your footprint PC. I've also found a project that is working to get biographical sketches of over 2500 suffragists across the country. They'll give you a couple names and a few months to come up with 500 words on the woman. They give you a by-line as well so you can claim the credit for the writing and research you do.
As everyone has said before, read, read, read. Find new areas that you aren't familiar with and put yourself through your own introductory course. I have been focusing on the War on Drugs and mass incarceration for my graduate school topic, but I've found that Australian history can be illuminating on this issue, though I know nothing about Australian history. So, I've taken it upon myself to learn the basics. On this same note, I usually carry a journal with me everywhere I go so that if something comes up and I think, "Huh, I'd like to know more about that," I can write it down and look it up later.
I think it all comes down to staying active in your learning and finding new ways to be excited by the process. Hope this is helpful.

A friend bought me Bolshoi Confidential as a graduation gift, and it's definitely as scandalous as you might imagine. (If not a little melodramatic - but that's how Russian ballet goes...)

@AP, my comment was specifically about the poster's comment about avoiding departmental drama and keeping their head down to do their work and only their work. That doesn't prepare one well for dealing with the drama that all workplaces have. Some of that department drama can have a direct impact on graduate students so it behooves students to at least pay some attention. (For example, my department ended up having a multi-year external search for a department chair. As a result, other faculty had to take on that work, leaving fewer advisors for PhD students and slowing down their grant/publication activity, which also affects PhD students. Consequently, a group of us paid close attention to the search and would explain to the faculty how and why we were being affected by it. That doesn't mean that we got dragged into being on the search committee but, it was something worth being aware of as a member of the department.)
I also think some people have a different idea of what it means to treat graduate school as a job than I do. For me, that means yes, you have friends outside of school but it also means that you have to build a network in school (in your department and around the university). It means working with people in your department. It means not being so selfish that you only focus on your own work, never pausing to help out others. None of those things are useful in the long-term as a grad student (and same for any workplace because no one likes the self-centered colleague who can never help anyone out with anything).
This last part might be because I come from an interdisciplinary field but, here goes anyway. If you don't have a broader understanding of your field and how to make your work interesting to people outside of your specialty area, then you're setting yourself up for a rough time on the job market (whether that's academic or not). One of the easiest ways to start learning how to do this is by having informal discussions with other students about what you're working on. If you're only there to go to class and do your own work (which is what the person I was responding to said), then you may not be allowing this to happen or you might view such conversations as a waste of time. My advice was a caution against that.