The shelter itself is a rock overhang, the kind of shallow cave that wild goat hunters and then shepherds used for thousands of years, and it belongs to the group of painted shelters that UNESCO listed in 1998 as the rock art of the Mediterranean basin on the Iberian Peninsula. They are the reason the road exists in your plan, and the road is good.
From the coast you climb through almond and carob terraces into a landscape of bare ridges, deep barrancos and small white villages hung on the slopes. The Serrella range stands to the west, and the twisty CV-715 and its neighbours between Castell de Castells, Tàrbena and Benimantell are narrow, well surfaced in most places and quiet outside August. Corners come tight and in long series, with sheer drops on one side and orange groves, then pine, then rock on the other. Early morning is cool and the light rakes across the cliffs. By two in the afternoon in summer the stone gives the heat back and the asphalt smells of resin.
People lived in these hills long before there were villages. The painted figures, usually small and red or black, show archers, animals and scenes that archaeologists argue about to this day. Much later came the Moors, and their terraces and irrigation channels still shape the valleys. You can read that layering in the place names that begin with Beni or Al, which are Arabic in origin, beside Catalan-speaking Valencian ones.
Do not count on finding petrol up here. Castell de Castells has a few hundred people and Vall de Ebo and Benimantell are smaller still, so top up before leaving the coast. The nearest real town for petrol, a supermarket and a lunch with a table is Pego, about twelve kilometres away on the plain, where rice fields spread out beneath the Marjal natural park. Bring water for any walk to the shelters themselves, wear boots rather than riding shoes on the loose scree, and leave the paintings untouched, because even a splash of water to make them show up damages them for good.