Lisbon
Lisbon is a wonderful, vibrant city and if you want to visit it whilst staying I would recommend finding an hotel and staying overnight.
The
drive from Casa Martin now takes only about three hours using the new
motorway (the toll is approximately €15). From the motorway one can
choose to enter the city by either the old 25 Abril Bridge or the new
slightly more northerly Vasco da Gama which is stunning.
Once in the city I would advise that you find somewhere secure to park the car as Lisbon is best explored on foot (wear comfortable shoes) and by public transport including the wonderful trams. A good guidebook is essential.