Comments please!
I haven't seen a published route, but I live between the two mountains so I know the riding as well as anyone. Neither are very weatherproof but great if allowed to dry out. The Coity has a fair bit of clay and is hard to navigate as it is quite featureless. The Blorenge is pointy rocks and soggy peat which is not to everyone's liking. Unfortunately The Blorenge's best bits are being sanitised by mis-guided, over-funded vandals from the forgotten landscapes scheme who think the public can't be trusted to walk on the anchient mountain paths without them being graded with imported stone. We can't have anything nice for long.
Might not be the best 'first real mountain biking' experience for a keen ten-year-old then... might just stick to Cwmcarn...!
My lad at that age found the rock gardens a bit disheartening. Could knock his confience a bit perhaps.