I beleive that the depot had a guard of around 2000. I also think I remember that Grant court-martialed the commander for setting the stores on fire and abandoning them as Price approached.
I agree that Price wasn't afraid to face Rosecrans. As Rosecrans approached, Price did not wait for him, but moved out to meet the threat. I think Ord sitting outside of town to the NW had a lot to do with his decision to leave prior to daybreak the next day.