As civilization headed toward collapse, Skye was trained as a high level assassin/mercenary and given multiple high tech tools. Just prior to the collapse, her boss/mentor and his wife anticipated what was coming and sent Skye to a bolthole they'd prepared just outside of Palisade, CO (we've actually picked the specific building on the Grand Monument). They'd intended to join her, but never made it. As she raced to CO, she stopped to bring her much younger sister with her. Once at the bolthole, she was able to build a life by gardening, hunting, raising goats and chickens, and trading with the townsfolk in Palisade (one of the few stable communities post-collapse) for the other things she needs.
Right now, we are thinking that Skye arrives 2-3 years after the collapse, so that she's still an outsider.
What Skye doesn't know is that researchers in The People's Republic of Boulder have uncovered records about the bolthole. They send a squad of mercenary types to investigate and retrieve the rare elements cache.
The first novel starts with Skye out hunting (introduces the tech and her skills). She returns to her cabin to interrupt two raider scouts harassing her sister. She kills them and gets evidence that there are more around. For prudence, she retreats to town.
The rest of the raiders show up in town as travelers/traders (think of gunslingers who wander into a town). Sky confronts, there's a fight, the sheriff gets killed. Various politics occur because Skye is clearly the best fighter around but she's a loner and really doesn't want the sheriff's job. Meanwhile, an arrogant rancher, [[Big Hat]], does.
Tension escalates as the raiders terrorize the town (attack the power station, etc.) all in an effort to get the town to hand over the cache that none of them know anything about.
Skye eventually beats the raiders. When she finally takes out the leader (who's a tough former unenhanced special forces type), she discovers he has a working satellite phone, when none are supposed to be working. Thus, she learns that he's been sent by someone more powerful.
Tee up second book in series.