do you mean river dart country park?
if you do,..then loads to do with kids...loads of play areas, pirate ship in middle of lake and man made beach...you can pre-book activities like canoeing and rockwall climbing, easy access off the main A38 road, but still feels like you are in the country.
lots to do in the area - just a hop up over to Dartmoor on one side and the other side you have the coast - dartmouth and the south hams.