I thought this could be a useful illustration:<br/><br/>(http://www.wildlife-art.co.uk/media/images/pictures/Roman-villa-P-Bull_t_mw580_mh350.jpg)<br/><br/>It shows the vestibulum (centre right) and atrium well with the impluvium and some principal rooms - oecus and tablinum (nearest). This sketch shows a variant with an upper storey, so instead of the cubiculum being beyond the atrium, they are above it, with the piscina and peristylium beyond shown as a walled and colonnaded courtyard.<br/><br/>The room in the front corner is a shop, probably not to do with the household at all but in the same structure. I've seen similar layouts at Herculaneum. This one looks like it might sell wine or oils and could be a part of the Caelius property.