Start at the Museo Río Cuale, a joint government-volunteer effort near the downstream tip of Isla Río Cuale. Inside is a fine three-room collection of pre-Columbian ceramics excavated in Jalisco, Nayarit, and Colima, including some especially attractive female sculptures and some charming representations of Colima’s famously fetching dogs. The museum’s website, www.tiendadelmuseo.com.mx, illustrates a number of for-sale examples. Find the museum open 9 a.m.–2 p.m. and 4–7 p.m. daily. Admission is free.

Head upstream beneath the bridge and enjoy the shady paseo of shops and restaurants. For fun, stroll out on one of the two quaint suspension bridges over the river. In the evenings, these are the coolest spots in Puerto Vallarta, as night air often funnels down the Cuale valley, creating a refreshing breeze along the length of the clear, tree-draped river.

The Río Cuale was not always so clean. But once upon a time, a few dozen foreign residents, tired of looking down upon the littered riverbank, came out one Sunday and began hauling trash from the riverbed. Embarrassed by the example, a neighborhood crowd pitched in. The river has been much cleaner ever since.

Farther upstream, on the adjacent riverbank, stands the Mercado Municipal Río Cuale, a honeycomb of stalls stuffed with crafts from all over Mexico. Continue past the upriver bridge (Av. Insurgentes) to Plaza John Huston, marked by a pensive bronze likeness of the renowned Hollywood director who helped put Puerto Vallarta on the map with his filming of Tennessee Williams’s The Night of the Iguana in 1963.

About 100 yards farther on, stop in at the small gallery of the Centro Cultural Vallartense, a volunteer organization that conducts art classes, sponsors shows of promising artists, and sometimes invites local artists to meet the public and interested amateurs for informal instruction and idea exchange. Ask the volunteer on duty for more information or see the community events listings in Vallarta Today or the Vallarta Tribune, the local English-language newspapers.

A few more steps upstream at a small plaza stands the headquarters and auditorium of the city-sponsored Centro Cultural Cuale. On the left side of the courtyard are the Centro Cultural’s graphic and fine arts courses. (Schedule of courses open to the general public posted by the Centro Cultural’s office by the auditorium, open 10 a.m.–2 p.m. and 4–7 p.m. Mon.–Sat.)

Walk a few steps farther upstream to the boulder-strewn far point of the island, where you can enjoy the airy river panorama: clear (in dry season) rushing water framed by great riverbank trees, verdant canyon ramparts, and distant cloud-capped mountains.