Transportation options from Porto

You can take a regional train across the border to Vigo, while not too interesting in itself it is connected to the Spanish high speed train network. Or you can continue north a bit to Santiago de Compostela or A Coruña. Both cities are well worth a visit (unless the tour visits them). The Spanish Atlantic coast is also underrated in my opinion.

Have you considered staying in Portugal and seeing the rest of the country not covered by the RickSteves tour, and you can use the train.

yes, for a few days, then I would like to head to France &/or England and eventually fly home from there.

With Skyscanner, you can pick a city and date, and see where you could fly.
https://www.skyscanner.com

I flew from Porto to Funchal, Madeira where I spent a week. I really enjoyed Madeira. I then flew from Funchal, to London. Both flights were non-stop.

I wrote about some of the things I did in Madeira on this post:
https://community.ricksteves.com/travel-forum/portugal/madiera-without-a-car

If you want to get an idea of which cities you can fly directly from Porto, you can check the wiki page for the airport to see airlines and destinations from Porto:
https://en.wikipedia.org/wiki/Porto_Airport
For example, easyjet has nonstop flights to Bordeaux and Nice if you want to head to France.

Thanks, everyone. I now have so many options. I also found a website called flightsfrom.com which looks very helpful. I put in the Porto airport and got lots of choices.

Have you been to Braga to see Bom Jesus? Not sure if it's covered by your tour.
It's a short train ride away from Porto.

When will you go? It matters a lot.