In reply to edordead:
Years ago we took our 9 and 10 year olds scrambling along the base of the Porthguarnon face (on the walk in to St Loye, just beneath Treverven camp site) at low tide and then found a way out at the far end. We also did a Diff there that they enjoyed (see my photos). It all had an adventurous feel without me having to worry too much. Depending on what you mean by toddler, it might be worth a look.
There are also a few places where you can scramble off beaches without doing anything too hard or recklessly dangerous. At low tide, a nice circular walk is between Chapel Porth and Porthtowan, out along the beach and back along the coast path. Near the Porthtowan end there is a point where you can cut easily up the path by a fun rocky scramble. I haven't done that for a good 10 years mind, so the sands may have shifted in the meantime. There are also nice scrambles among the boulders going the other way along the beach from Chapel Porth, also at low tide, with an interesting addit that you can peer into some way along.
Further along, on St Agnes head, you can walk down to Tubby's Head and scramble about on the rocks, getting the feel of being somewhere wild without doing any actual 'climbing'. I used to do it with my daughter when she was 5,6,7 or so.