FOR MANY hoofers hereabouts, a highlight of April is the C & O Canal Association's annual hike. This year's edition starts at White's Ferry on Saturday. As a warm-up, we took a stroll the other day along the Georgetown stretch of the canal and found it cheerfully aswarm with strollers, joggers, cyclists and mules. Ah, yes, the mules are finally back, toting a new passenger barge and its lively crew on two-hour rides up the canal from the landing at 30th Street. The landing itself has been enlarged by the adjacent Inland Steel development, which also houses a National Park Service center for visitors.

The information office is very welcome because there is little else there to tell people about the old canal or the rich history of the Potomac and the Georgetown waterfront. Most of the cross streets don't even have signs identifying the national park, much less disclosing that it stretches 185 miles upriver. Of course, good guidebooks are available. But in a place so full of history and pedestrians, features like the canal should be subtitled with small, tasteful signs and displays to educate visitors while they walk.

We have in mind little signs that they say something - not plaques like the one on the Renwick Gallery, which proudly announces that the building is a landmark without disclosing why. Some Park Service planners have the right idea. Now floating around in the bureaucracy is a proposal for the lower end of the canal that suggests new brochures coordinated with modest displays at intriguing points, such as the Alexandria aqueduct abutment besides Key Bridge. This should not cost much, especially if interested citizens are mobilized to help. The effort might even inspire neighbors of the canal to enlighten passers-by about other properties with a past. It is, after all, a historic park in a historic district. People should be told more about what is being so carefully preserved.