Hey!
Vacationing to Harper Rock sounds like a recipe for disaster.
Though it's really great, I imagine, for someone in Nathan's field. I can offer up either Az or maybe Salvator for plotting? I mention Az because he's an academic - though their areas of focus don't have a ton of overlap (unless Nathan has a love for dead languages).
But in general, Az is fairly easy to get along with, which I find tends to make plots with him pretty easy to sort out.
Salvator I actually need to write more with. He's a memoirist who loves history. His move to Harper Rock is a bit of a pre-mid life crisis. The last of his family (save for his wild child sister) have all passed, and he's the last of the Hastings - which sort of prompted him to want to bury some roots. Of course, then the Rift expanded and zombies are all over the place, so that's happening.
He's extremely well traveled, and a tiny bit pretentious because he grew up middle class, and is independently wealthy. Mostly though, he's a good guy.
Sorry, I suck at describing characters.