2 weeks in Portugal in September

Make sure you return rental car in Portugal to avoid large drop off fees.There is no charge to cross borders.
Allow enough time for Santiago de Compostela. I would skip Vigo, visit Pontevedra. Go farther up the Rias Baixas to O Grove. One night is not enough time to see all you have listed in Galicia. Santiago de Compostela is a favorite of mine but it is a city, takes time to find parking and/or your hotel.
We spent two nights in Guimares, again you are not allowing enough time.
Four days( which means five nights) is good for Porto. Tour the historic center, take a day cruise up the Duomo, then go by train back to Porto.We liked staying in historic center a few blocks in from the river. Or on the river.
Book tours directly rather than using Viator which is an extra layer. A good hotel can book tours for you.

Thanks so much Suki! I value your input.

You mentioned driving to Galicia just to stay 1 night, right? Then I would head straight to Santiago, and go no further. And I would stop in a coastal location on the way back; o Grove is one but Baiona springs to mind as it easier to reach, and the coast road from Baiona to the border is very scenic.

I agree that one night in Spain isn’t nearly enough for the places you mention. It’s a fair drive from Porto. But, it’s beautiful. You could potentially drive to Guimaraes and Braga on the way.
An organized day tour to the Douro is quite nice as you don’t have to worry about driving after doing the wine tastings!
With 4-5 nights, an apartment will be more comfortable. Stay as close to the river as you can.

Matosinhos, outside of Porto is a lovely place for a grilled fish lunch. And, don’t miss Gaia for the port lodges. Some do regular wine, too. Taste Porto food tours are a great way to be introduced to the food while getting a bit of history about the area.

@balso! great idea! Thanks for chiming in!

@kathrynj Thank you for the food advice and lodging suggestion. Will definitely look into that.

All above, thanks for the information regarding spain. Definitely rethinking that part of the trip. Might be too much to do. I appreciate all of your suggestions/comments. ~M

Definitely go see Bom Jesus in Braga.

I also love Santiago de Compostela and Pontevedra. Don't forget to enjoy razor clams, a specialty in Galicia.

Check car hire companies carefully. We have rented in Portugal three times when we have taken the car into Spain. Once there was no additional charge, another charged us a premium for the days the car was in Spain and another charged us more for the entire trip. When trying to hire cars, we have seen additional costs of €20 - 50 a day to go into Spain.

I would try to book any tours direct rather than using Viator who are just a third party seller.

I agree with all the others: The Spain plan isn't going to work. Galicia is lovely and the towns mentioned so far are worthwhile, but there are others as well. And east of Galicia are other great places. I urge you to plan another trip across northern Spain rather than peeling off just a day or two from a trip to Portugal. There's plenty to see in Portugal.

Hi Barkinpark, Jennifer, and acraven,
I really appreciate your feedback and suggestions. Looks like Galicia isn't going to work out - next trip! Lots of great information from everyone!