Day 1: the old city
Grand Palace at 8:30, Wat Pho, ferry to Wat Arun, then a long lunch and nothing else. The heat, not the distance, is what exhausts people.
Day 2: river and markets
Morning longtail through the Thonburi canals or a cycling loop in Bang Krachao; afternoon at Jim Thompson House or a spa; evening street food in Chinatown.
Day 3: get out
Ayutthaya by train or Kanchanaburi by road — both are full days and both are better than a fourth temple in the city. Alternatively, a cooking class and a rooftop.
Where to stay
Riverside for a first visit (ferries become your transport); Sukhumvit or Silom if you care more about food and nightlife than temples.
