Parc de la Croix-Lumineuse is a lookout above Lac-Mégantic, reached by road and marked by the illuminated cross on the hill. From the Rencontre au Sommet area, at about 500 m elevation, the view opens over the town, lake, and surrounding hills.
It is a short, easy viewpoint rather than a full hike. Bring binoculars if you have them, and use it as a quick orientation stop before heading back to the waterfront or out toward Mont-Mégantic.