Ok I will start with Professor Herbert Eugene Bolton’s map of the area. He visited the site about 1908. And published this map in 1914 in his “Texas In The Middle Eighteenth Century. The one east/west road on this map
Is now state farm to market road 908 and continues on east to the city of Rockdale approx 9 miles away.
Here is the marker for the Candeleria mission.
As you see on the map it was the furthest west mission on top of a ridge. Down in the bottom land looking west from Candelaria to the location of the presidio. ( big pecan trees in center of photo is pretty close to presidio location. The old irrigation ditch would have been in this field. Chances are this field was under cultivation in colonial times!