Good day to everyone! I'm hoping to get some assistance with our one day in Sintra - I know we are trying to fit in a lot but we have other obligations, so one day is all we have.

We will be driving from Porto early morning, and thinking of going straight to Cabo da Roca for a few hours. We plan to return our car after Cascais and spend the afternoon in Sintra. Is it possible to fit in the Moorish Castle, Pena and National Palace in one afternoon, and if so, how would you suggest we plan? Or should we skip Cabo da Roca and concentrate on Sintra? Also worth mentioning is that this is on May 1 which happens to be a national holiday.

I very much appreciate the advice!

I'd stay in Sintra to do all those things at a leisurely pace. Cabo is neat but little there. Stay in Sintra and drive via Cabo and Cascais next day.

No, I'd say it's not possible to do all of those sites well (or even at all on a crowded holiday). You will be rushed trying to fit all of that in and it will be crowded so you will likely not be able to move quickly even if you'd like to. Also, transportation up and down the mountain and between sites took much longer than expected. For reference, I started out on the earliest bus of the morning, and I fit in Pena Palace, the Moorish Castle, and the National Palace in one day and Quinta de la Regaleira and the Palacio do Monserrate on another day.

Personally I thought Pena Palace and Quinta de la Regaleira were the most interesting. Pena Palace sits on a huge swath of grounds, so you'll want to make time for exploring the beautiful forested grounds, as well as seeing the palace itself. Quinta de la Regaleira is full of caves and passageways and towers, etc. - it's beautiful and really interesting. (I also really liked the Moorish Castle, although not as much as Quinta, and I'd say you can skip the National Palace without worrying that you're missing a must-see site. The view you get from the outside is the most interesting part.) Also, I strongly recommend Cafe Saudade for lunch or a snack - cute little cafe in the heart of town with lots of menu options.

I'll echo PalenQ's advice to do Cabo da Roca and Cascais on one day and then plan to spend a full day in Sintra.