Two very different landscapes in one day: Sintra's hilltop palaces first, then Cascais's Atlantic coast or Quinta da Regaleira's underground tunnels. Pena Palace entry is skip-the-line, included.
Sintra's Pena Palace draws the day-trip buses early, and the courtyard queue can run past an hour by mid-morning. This private day includes skip-the-line entry, then a guided walk through Sintra's old town, and an afternoon split between Cascais's coast or Quinta da Regaleira's underground tunnels. It works best for travelers who'd rather do Sintra plus the coast, or Regaleira, in one day than split them across two separate bookings. Skip-the-line entry means you walk into Pena Palace when your day says so, not when the ticket queue allows it with the coast or the tunnels still ahead.