There were probably 18-20 rooms in total in the central core of the mission which contained the padre’s quarters, storage rooms and workshops (for carpentry, candle making etc.) and young women’s housing. There would have been other buildings in the complex, soldiers quarters, housing for the major domo, storage buildings, neophyte housing and a blacksmith shop.
The missions grew most of the kinds of fruit you would be familiar with, apples, grapes, melons etc. Most missions grew wheat, barley, corn, beans, peas, lentils. Because it had an excellent climate and was well irrigated, San Buenaventura also grew exotic crops: coconuts, figs and sugar cane, for example.
The primary source of income for most of the missions was cattle hides and tallow. San Buenaventura was not a “powerhouse” like San Gabriel or San Luis Rey, but they had a herd of about 4,000 cattle and 3,000 sheep.