Since no one has reviewed Valença yet, I thought I might. I cycled around the area on the last day of August 2021. Valença is a fortified city on the banks of Rio Minho in northern Portugal, bordering the spanish city of Tui (nice cathedral). The site is pretty impressive, the forteress is massive. You can really tell how fortify is A Raia (portuguese-spanish border). The historical center is a nice charming classic northern portugal old city with lots of artisanal shops. Regular trains connect Valença with Porto everyday, as well as with Vigo in Spain. There are also buses.
I visited Marvão during an Alantejo road trip in October 2020. We arrived in the morning and lost 7 degrees from warm 20° Elvas. The village is located near Portalegre in the Parque Natural da Serra de Sao Mamede, next to the border with Spain as well. The village is built on a rocky hill and includes a very pittoresque old center as well as an impressive castle looking over the valley.
Both site are very impressive and enjoyable. I'm really looking forward to visit Almeida one day.