Most visitors do Rattanakosin in one breathless dash through the Grand Palace and out. This is the version where you skip the lines and walk the lanes between.
Start at Wat Mahathat after lunch — a working monastery whose meditation hall is open to non-monks for free. Cross the road to the City Pillar Shrine, then cut through Saranrom Royal Garden. The garden was the king's private grounds before it was opened to the public; the lily ponds and old rain trees give twenty minutes of cool air before the next stop.
Museum of Siam is the smartest hour you'll spend on Thai history all trip — interactive, ironic, in English. From the back gate you're a five-minute walk to Tha Tien pier and the Make Me Mango stall on Maharaj Road. Order the classic mango with sticky rice and coconut cream; eat it in the courtyard upstairs. The riverside view is included.
Finish at Amorosa, the rooftop bar at Arun Residence directly across from Wat Arun. Time it so the temple's prang lights up at 18:30. One drink is enough.
