We (two parents with son of 16) stayed in Helena's place, close to Porto, for one week. The house was fine for us, although cooking an evening meal is somewhat complicated with a single electric stove. There are plenty of supermarkets closeby, we did our shopping at Supercor Fluvial. Getting to and from the city centre of Porto takes some time. There are several buslines (and a historic tram) but one has to be patient. A rented bike is usefull, for exploring the coast or riding along the river (Vueguini rental). It takes 1,5 hrs to get with a rented car to from Helena's place to the interesting parts of the Douro valley and vinyards. On walking distance is the Foundation Serralves, museum and garden. Very nice!
Thanks for having us, Helena!