10 days in Portugal in late August - Suggestions

A few thoughts when I read your post:

go all the way to Cascais to explore the little dazzling beach town
take a tour with the Eléctrico 28 and be awe-struck at the monastery of Belém

Did you copy and paste this from some tour itinerary or something? I mean, Mosteiro dos Jerónimos is quite impressive, but who uses the expression "awe-struck" these days? ;-)

Dinner in Cascais

I have planned a lot of trips, but one thing I've never done is schedule where I would have dinner about 3 months before the start of my trip. I point this out as an example of what your itinerary in general is missing: spontaneity.

Tavira tourist train

I saw that thing driving (it's not a real train, actually) around Tavira several times when I stayed there in late March. To be honest, I don't see the point of spending money on a tourist trap like that unless you have walking problems (but in that case most of Lisbon and Porto with their steep streets would be off limits too); Tavira's center is quite small and easy to get around on foot.

Ria Formosa national park

We made a 3-hour boat trip from Olhão around the park, but to be honest I found it slightly underwhelming as far as bird sightings and natural beauty go.

Yes, some of that had been cut and paste from travel sights or other posts. They are just little notes to give us ideas. What I am more concerned about is the general itinerary and if we are staying in good places, and seeing what we should be seeing and not missing anything major while still having enough time to enjoy the places we are going.

Of course there are a great many other interesting things to see and do in Portugal. If they are more interesting than the ones you have chosen is not for me to say, because it depends on what you expect to see and experience.

You like fish?

Then visit Setúbal or Sesimbra.

Hi,

I think you're doing tick the box tourism and not really trying to see and feel the places you're visiting but that's OK if you feel comfortable with it. I think you'll be exhausted after the first day and you'll end up changing some of you travel itinerary.
If I were you I would skip the Algarve since you'll be traveling to Rome from Porto.
Alentejo region, where Evora is the capital, has a lot to see and to feel and to do. But you have to do it in a calm way. That's just how the region is and should be savored.
A boat trip in the Alqueva, wine (this wil be early September, maybe you'll end up doing some vindimas or grape harvest), olives and cork tree experiences. Feel the evening heat on your skin while having a great dinner. Seeing all the castles in the region like Monsaraz, Marvão (the most beautiful in my opinion, don't skip this one), Estremoz, Vila Viçosa (for a great palace), etc. This has to be done in 2 days.
Besides this note and think it is doable.
Day one, I'd skip Carcavelos.
Get off the train in Estoril and walk to Cascais? It's about 2,5 km walking from Estoril train station to Cascais center, I don't know if you'll be tired or not but I'd skip it also.
To be honest, Cascais is best seen under daylight.
You should arrive early in the morning, after a good night sleep, get a free bike, go to Praia do Guincho, there's a next to the ocean bike path, have lunch over there looking at the westernmost part of Europe, Cabo da Roca. Unforgettable.
If you'd like to stick to your plan there's always something going at night in Cascais central plaza where everyone goes to dinner and drink. Its bay is also very picturesque at night because of the fisherman boats and the light of moon. Just sitting and watch people go bye is great.

From Évora I'd go to Óbidos and do what you planned to do. On your way to Porto, stop at Alcobaça and Batalha for the monasteries. They're both must see. There's no way you'll get to Porto mid day. Maybe late afternoon, just in time for checking in at the hotel and go out for dinner.
It's also impossible to do what you planned in one day as you say, see wineries and river cruise.

Maybe I'd stretch my way from Lisbon to Évora a little bit and have lunch at Comporta beach, in the Troia Peninsula. Best white sandy beaches in the country, good food also. Then from here to Evora.
So, 3 days in Lisbon, 1 Sintra, 1 Cascais, 2 around Evora, 1 obidos, 2 Porto.
If you're putting the Algarve here you won't be seeing anything else.

I love the Algarve. Great place for a beach vacation. The water is calm and hotter. Great cliffs. Good food. Very nice fisherman villages, but it needs a few days.