You can spend an afternoon studying the exhibits at Giant Catfish Museum during your trip to Chiang Khong. While you're in the area, stroll along the riverfront.
After visiting Wat Phra Kaew, make a plan to see the other sights and activities in Chiang Khong. While you're in the area, stroll along the riverfront.
Though Chiang Khong Crown Prince Hospital might be what brings you to town, perhaps you'll have a chance to explore more of Chiang Khong while you are here.