Fast answer
A strong Menaggio western-shore day starts with Villa Carlotta or the Greenway, not with collecting every town. Villa Carlotta controls the calendar, ticket, and last-entry layer. The Greenway works when a walking day is more valuable than another ferry crossing. Cadenabbia and Tremezzo can support the day, while Loveno belongs only when the hill context fits the route. Heat, rain, ferry or bus returns, and ticket timing should decide how much the day carries.
If you only do one thing
Start the day with Villa Carlotta or a Greenway section, then add Cadenabbia, Tremezzo, or Loveno only if transport, weather, walking time, and return options leave enough slack.