I have dynamically injected features to a single vector layer working now, and can store EPSG:4326 co-ordinates in an array and transform them on the fly to EPSG:900913 co-ordinates. I've settled on some form of JSON to pass the arrays (from the DB) to the map, as it appears to be the easiest way to add the array to my existing layer. Using anything else requires contortions or its own layer. The downside of GeoJSON seems to be that it doesn't seem to have the ability to store info like titles and links (CDATA, basically). I can make up my own, but...

I'm now working on a development version of the DB so I don't blow anything up.
Docs here should provide some info for creating the polygons.
Questions: in our case am I working with actual polygons or can I get away with a delimited set of coordinates?
I'm not using MySQL to determine things like area or length, so is using the spatial extensions a waste of time?