I will be visiting Basque country and the Pyrenees in August. The plan calls for 3 nights each in the following towns:
Barcelona - point of arrival and departure. After 3 days here I will pick up a rental car and drive to Bilbao.
Bilbao - first day will be mostly driving from Barcelona, followed by two chill days in Bilbao and visiting some nearby sites: Gaztelugatxe, Bermeo, Mundaka, LaGuardia.
Bayonne - visit SS on the way from Bilbao, then chill in Bayonne and/or SJ de Luz. Can also take a drive in French Basque countryside and visit nearby Basque villages.
Sallent de Gallego - Hiking in Ordesa y Perdido, Tena Valley, and the French side
Huesca - will likely have two full days here. One day for Huesca itself and another for optional day trips to nearby sites. Close enough for departure via Barcelona without excessive driving.