Guest House Casa Prata, is located in Rua da Escola, 4 - Estoril, easy accessible from the  Av. Marginal. 
Click on the map bellow to see more detail.

If you come from the motorway (A5), take exit Estoril, on the second roundabout turn left, you're entering the Av. dos Bombeiros (where the Fire Station is).  Follow the road signs. When you must turn left (you can't go straight on), Casa Prata is at the end of road your entering.