Looking to take a trip to Portugal with 2 other couples all in our early 60s and physically fit. We have one week (8 days/7 nights) to see as much of the country as we can, starting in Lisbon. I have been to Lisbon a couple of times for business and had some spare time to walk around the city but would like to explore the city in more detail and get up to Porto and the Douro River Valley. Any suggestions of the top sites/cities to see outside of the ones I mentioned and whether or not to take a tour (if so, any suggestions on which ones?) or to use trains/and or cars to get around? Thanks in advance!
You could see what sites appeal to you in the AT A GLANCE section here:
https://www.ricksteves.com/europe/portugal
The highlight for us was Obidos. We stopped there on the way from Lisbon to Porto. Here's a link to my Trip Report which may give you some ideas. https://community.ricksteves.com/travel-forum/trip-reports/trip-report-part-1-hills-and-castles-portugal
Since you have so little time I would divide my overnights between Lisboa and Porto. It is barely enough time to do justice to those two but you could always do day trips (Cascais/Sintra from Lisboa and Douro from Porto).
I agree with Scott, 7 nights is not very long and you should probably limit yourselves to Lisbon and Porto. If you haven't booked tickets, you should consider flying open jaw so that you do not have to double back to Lisbon and waste half a day.
We were three couples traveling in September, 2023. FWIW, we rented a nice three-bedroom apartment in Porto from feelporto.com and this lovely three bedroom apartment in Lisbon: https://www.booking.com/hotel/pt/blue-by-the-river-4-unique-penthouse-duplex-with-a-view.en-gb.html
Each couple got their own bedroom and bathroom and there was lots of living space to socialize and dine, and a washer dryer for laundry. Locations were good.