I don't think that there is any crag in the Western Cape (maybe the whole country?) where you have to rap in. Anywhere there are bolts at the top of the route you can top rope, just put your own quickdraws into the bolts at the top to reduce wear and tear on the bolts.
Lower Silvermine is a good place and the top bolts are usually positioned in a rope friendly place. Peer's Cave isn't bad either if you are a beginner but take along some slings to extend the draws over the edge to reduce wear on your rope. Kleinmond has lots of easy, toprope-able stuff and then there is Montagu too.