Was there last month.
Head down to the old town for the Port Cellars, restaurants and bars.
The cable car is a nice way of getting from the old town up to the top of the Dom Luis Bridge, walk over the bridge and then the funicular down the other side. There’s some great views up and down the Douro.
Doura river cruise was interesting
If you have a car and kids then a drive down to Portugal dos Pequnitos (small houses of portugal) in Coimbra is a fun day out.
There’s some great bike paths along the river to the beach.
There’s also a local speciality called a Francesinha sandwich, made from Steak, Sausage, egg and covered in cheese which is pretty good when you find a good one, although these are a bit rubbish in the tourist areas.