The Camino Levante begins in Valencia in the south of Spain. The route is 800 Km from Valencia to Zamora. At Zamora, it joins the Via de la Plata. From Zamora to Santiago de Compostela you will have three choices. You could walk north to Astorga where the Via de la Plata joins the Camino Frances and then follow the Frances to Santiago. You could walk north through Astorga and continue on to Gijon and then walk the balance of the Camino del Norte to Santiago, or lastly, you could take the Camino Sanabrase which goes across the mountains and through Ourense and on to Santiago. The least of these choices will add another 400 km to your journey and some even more.
The Camino Levante is well-marked thanks to the pilgrim association of Valencia. Pilgrim Association of Valencia It is very important to buy a guidebook from the association as there are not many sources of information about this route. The association has an office with limited hours. It looks like it is open in the morning on Wednesday’s and the evening on Fridays.
Here is another link to information about the route. Vivecamino.com