The Mirador San Jorge sits above the road between Sololá and Panajachel, looking down over the town and across the lake. It is a simple stop, but the angle is excellent: roofs in the foreground, blue water beyond, volcanoes closing the horizon.
Take a taxi or stop with a driver rather than trying to walk the busy road. The view is best early in the day, when the lake is still and clouds have not yet gathered around the peaks.