b658aed6__World_Interactions___UESPWiki__Details
[Encounter Name] Dawnguard OutriderDG [Options] She will only tell you to "Stand Aside!" if you get in her way. She carries a key and a note that give access to Dawnguard supply caches. [Requirements] Complete either The Bloodstone Chalice for the Volkihar vampires or A New Order for the Dawnguard. [Details] 
You encounter Saliah on the road.
Skyrim:World Interactions - UESPWiki
Details