We were three adults and had a wonderful time in Vila Nova de Gaia in the charming and comfortable flat. It is perfectly located, and everything you need is either in the flat, or across the street at the market.
Porto is just across the bridge which is only a five min. walk from the flat. Once I figured out the back way down to the river, going up and down was very easy. I suggest going down General Torres and then look for the stairs to the left once you see the river.
Host Wise communication was great, and we highly recommend.