Piódão is an adorable schist village (sometimes called the 'nativity scene village of Portugal') perched in the mountains 100 kilometres east of Coimbra. I'd highly recommend a visit as it's possibly one of the cutest places you'll ever see (along with Monsanto, which is conveniently located in close proximity).
Given Piódão's remote location it's most easily reached by car, and while you're road tripping you can visit other towns in the nearby Serra da Estrela Natural Park such as Manteigas and Sandomil.
There are hiking trails near Piódão that let you explore Portugal's peaceful mountain landscapes.