As for your questions, I think maybe you are trying to over-orchestrate things. I'm sure there are at least some disaster preparedness jobs on military bases, but I think trying to plan down to that level is a recipe for disaster. You are asking the wrong questions, IMO.
Instead of "can she get hired on a base'", ask in general if the job/career field is something that will be needed in most locations. Because even if bases have a few of those jobs, you can't rely on them being available in windows that match your orders. So what you want is a job that exists in most places, and also one that doesn't require state certifications (for the most part, though there are exceptions, but I won't go into them since it sounds like that doesn't apply.) So something common at a university, for example would be better than theater-- field where paying jobs are scare in most locales.
As for a "good degree for a spouse", I think the answer there is largely "whatever she'd study if she weren't 'a spouse' ". Unless that is something like law or med school, I think most degrees that have value for civilian spouses and regular ol' people can be translated into something that works in a fairly portable career. The choices she makes after she gets the degree are slightly more important, and perhaps those should be made with potential portability in mind. And she also needs to know that even is she studied marketing, she may well end up working as a fundraiser at a university, which has naught to do with marketing, but is a job in a town where you end up. If she can be flexible, then you are 95% of the way toward your "paths working well together". But she needs to know that her career will take brutal hits, potentially. Maybe it won't, but that can't be counted on.
And I feel the need to point out that all of this is somewhat premature anyway. She'd be a fool to make schooling and career decisions based on her boyfriend's potential (have you already gotten a flight spot?) future career, just as you'd be a fool to make career decisions based on the feelings of your girlfriend. Like it or not, girlfriends come and go. So, I suppose, do spouses, but the odds are at least slightly better there.
