Most of this itinerary requires a car rental. It is recommended to book in advance to get the best rates. In some cities, such as Lisbon and Porto, public transportation is a great way to get around, and Uber is also widely available. Travel costs estimations are around $300 for car rental and $100 for gasoline.
If you have more than 10 days, consider adding a visit to the Azores islands for lush natural scenery and amazing whale watching. If you have less time, prioritize Lisbon and Porto, as they are the country's major cultural hubs. If relaxation is your top priority, consider staying more days in Algarve or adding a spa day in Alentejo. Remember to try the seafood and the local wines, and leave some time for unplanned adventures.