F**ck Dartmoor. It'll make you bleed, and anyway, it's not on your way. Do it like this...
On your way down the coast road, turn off to Hartland. Go to Hartland Quay.
Boulder here (on the right-hand beach, looking out - a good trench with several problems.
Back to the coast road. Look on your map, go to Northcott Mouth. Go left along the beach. Climb everything you find.
Back to the coast road, go to Si Young's wall
http://www.barn-climbing.co.uk, get grades and names for the shit you've done so far. If you've been super keen, you'll be nicely warmed up, so ask Si for directions and a topo to Upton, and get in amongst it down there.
back to coast road, and on to Newquay. Smart