The VSP and FFX Co FD are very close...IMO, they are working very closely on this case and each department could easily influence the overall path of this investigation. But you are correct, VSP is in charge and to some degree NM is one of their own.
Woodbridge, VA has been reported as where NM lives - Woodbridge is in Prince William County, VA (Southern end of the DC/Northern VA Metro Area)
Fairview Fire Station #32 (NM's work station) is at 5600 Burke Centre Pkwy, Fairfax Station, VA 22039 - in Fairfax County, VA. (Pretty much a central location for Fairfax County)
CrossFit Warrenton is her reported CrossFit Team/Group/Location at 32-34 S. Second Street, Warrenton, VA 20186 - in Fauquier County, VA (moving West of Fairfax County and becoming increasingly more rural with each mile in most directions from this point)
Syria, VA - is in Madison County, VA and is near the area of the Shenandoah National Park near the Whiteout Canyon Trail & Old Rag Fire Roads
(Not exactly sure where this location originated from so please fill me in. Also, have specifics been reported about what parking lot her car was located? Everything I read is non-specific.
A Google Map with all these locations is at this link
https://goo.gl/maps/NKKPwsHFRP42 for reference and comparison to the National Park Maps/Trails below....
Shenandoah National Park Map:
https://www.nps.gov/shen/planyourvisit/upload/whole_park.pdf
Shenandoah National Park - CLOSURES ASSOCIATED WITH ONGOING SEARCH (April 19, 2016) - https://www.nps.gov/shen/planyourvisit/alerts.htm - Also lists closures & links to fire area on a map.
Whiteoak Trail
Cedar Run Trail
Cedar Run Link Trail
Limberlost Trail
Crescent Rocks Trail
Skyland to Big Meadows Horse Trail between the Whiteoak Canyon Trail and the Old Rag Fire Road
Just thought it might help create reference and travel paths to consider. Also, it is VERY common for residents to live further south than Woodbridge or further west than Culpeper, Warrenton or even Front Royal to commute daily into the Fairfax or DC area for work. There are park and rides, van-pools, etc....
Also, IMO she seems like the unlikely type to call in sick for a shift on Wednesday to go for a run or training mission that far out of the way. From all accounts I would be willing to bet that she is NOT the call in sick type, which is why when she didn't call/show on Friday the red flags w/ horns blazing started.
Praying she's found soon.