So last January was my first time to Portugal. We loved it so much, so we went back over the Holidays in December for 10 days. We were in Lisbon, Silver Coast, Porto and Cascais.
My two best friends saw my pictures and...well we have booked a 1 week trip starting the end of this month to celebrate our 60th birthdays together.

Our priorities are to do day hikes (3 miles or so most days) eat and drink local foods and relax and have fun together.
I have yet to go anywhere south, so wondering what you might think of this schedule:
Arrive in Lisbon 9:30am, pick up a car and drive to Melides for 2 nights. Walks on the beach and parks, and relax.
Drive to Sagres (Pousada) and spend two nights there. Do either the bridges walk one way or the walks near Sagres, and if weather permits do a kayak trip to Bengali cave on last day and then head back to airport in Lisbon to drop the car and head to the city.
Stay in Alfama the last 3 nights. Do a food walking tour the first evening. Second day head to Sintra via train for the day and have dinner there at Incomum.
Last day walk and explore Lisbon.
We are from the midwest in the US so driving 3 hours isn't a big deal, But personally I am wondering if we should go all the way to Sagres. But it looks so beautiful!
Thoughts or suggestions please?
Thank you!

Driving within a day or two of crossing multiple time zones -- as when flying to Europe from the U.S. -- is much more dangerous, to yourselves and anyone else on the road, than is commonly recognized. Perhaps you could start with a day or two in Sintra, which you can reach by public transportion from the airport in Lisbon. (A car would do you no good there.) Then, after spending a day or two in Sintra (there's plenty do do there), go back to Lisbon by public transportation to pick up your rental car.