Any suggestions with regard to what area to stay in and what Airbnb is recommended in that area; looking for both
Barcelona and Madrid, 4 nights Barcelona, 3 nights Madrid?
In Madrid, to the east of Plaza De Espana in La Gran Via is in the middle of everything. It is very lively and people are out till way after 2:00 AM on a normal basis. Metro and buses are easily accessible.
We stay in the la latina area due to immediate access to tourist areas yet a quieter environment.
La Latina is my favorite in Madrid. Haven't used an AirBnb in Barcelona but I'd probably try to find one in the Eixample or near El Born.