Arrecife's centre is walkable. From the Charco de San Ginés to the Castillo de San Gabriel is about a kilometre, all on the level along the seafront. The pedestrianized Calle León y Castillo handles most of the daytime foot traffic.
For the Castillo de San José and its art museum, take a taxi from the centre — about a 10-minute drive — or use line 5 of the local bus. To explore the rest of Lanzarote, rent a car; the island's volcanic landscapes, vineyards, and beaches are spread out and reward a few days of independent driving.