Cuyutlan is about 20 kilometers south of Manzanillo and probably best to either rent a car or go on a tour that may combine with a visit to the turtle sanctuary south of town. You can access Cuyutlan from either the toll highway (right at the toll booth) or from highway 200 that runs through the country aways from the coast. There are buses but it would be a slow trip.
Excerpt from Dons article
On the plaza, face the school building and walk toward it. When you reach the street, turn right, heading toward the railroad station, and walk to the end of the next block. The museum is on the corner to your left.
The museum is open from 9:00 a.m. until 6:00 p.m. every day. Admission is by donation. Be as generous as you’re able. Clean restrooms are at the back of the main room.
Pride in Cuyutlán’s contribution to the history of Mexico is evident in the simple displays housed in this well-maintained recently re-modeled museum. It serves as a tribute to both the 16th Century salt harvesters and the modern salt producers, the salineros, who work from March to June in the salt flats of the 35 kilometer Laguna de Cuyutlán, the Cuyután Lagoon.