I am interested in getting to either Peso da Regua or Pinhao for an overnight in a Quinta, but I am only seeing round-trip options from the tour sites. It would be nice to take the boat there, stay overnight in a Quinta, and then take the train or a van back. Any advice in this regard is appreciated!
Try this: https://www.cruzeiros-douro.pt/en/1-day-cruises/oporto-regua-oporto-cruise-upstream
Contact the tour and see if they will deduct cost of the bus ride or arrange for you to take bus the following day. Good luck.
I don't have an answer, but I attached a blog that has information about visiting the Duoro valley. One thing to note, the best scenario by boat is upstream from Pinhão. So you might consider taking a train to Pinhão and then taking a round trip boat cruise from there. I'd pick the train over a van since it goes closer to the water.
https://juliedawnfox.com/explore-douro-valley/
I am inclined toward the train to and fro with a boat ride out of Pinhao and back. But the information for both options is appreciated! love this forum!