If you are staying in Playa Blanca then get the ferry aross to Corralejo on Fuerteventura and then a bus out to Tindaya which is a half decent hill.Don`t know if you still need a permit as it has sacred carvings on the top .I never bothered ,Montana Rojo (?) at the southern end of the Corralejo dunes gives an hours or so walking and decent view and if you walk back along the coast through the dunes you may want to leave any inhibitions you have behind !
If you want a good hill day then get the first ferry across and hire a car,drive down the length of Fuerteventura and do a few hills on the Jandia peninsula.Cracking views down there and well worth the price on a good day.
Nothing much on Lanzarote intereste me other than a few volcanic bumps in the south.The highest point on the island is closed to the public courtesy of the Spanish military.
Watch the sunset at El Golfo on the west coast,take a trip down the Ceasar Manique (?) cave,and the Timanfaya is worth a visit.I had a car for a week and ended up doing the same things over and over
I`ve got guides for Fuerteventura here and may have one for Lanzarote.If I have the Lanzarote one I`ll drop it off or you can pick it up when passing.