Consider taking a bolt from your condo in Lisbon directly to the Pena Palace to beat the crowds before the entrance opens. According to google maps, an economy bolt is currently estimated to be €22, 1 minute wait, 55 minutes ride. Price will vary depending upon the size of the bolt that you choose and demand.
When you take the train, you will be in a crowd with hundreds of other tourists all vying for bolts, the bus or tuk tuks at the Sintra train station. If you arrive at Pina Palace after 10:00 a.m., there will probably be a huge line up.
If you are sharing a bolt from Lisbon with at least one other person, you will find that the cost per person is not much more than taking the train and the bus up the mountain. I think the bus pass for the mountain is €10 per person.
There are lots of bolts in Lisbon, less so in Sintra. At 8AM, we only had to wait a few minutes to catch the bolt in front of our condo. We paid €35 for a large bolt XL for six people. We arrived at Pena Palace by 9AM. We had pre-booked tickets for the first timed entry. We toured the interior and the terraces. By about 10:30, the crowds and line up were huge. We ate lunch in the restaurant; nothing special, typical cafeteria food. We then walked over to the Moorish Castle, bought tickets at the entrance and spent about 90 minutes there. This was not too crowded because everything is outside and spread out. By about 3:00 p.m., some of us were tired and wanted to go home, so we ordered a bolt back to Lisbon. We had to wait for about 20 minutes because there are fewer bolts in Sintra and they had to drive up to the mountain to get us. For the six of us, it cost only €28 to return to Lisbon.