Dates are flexible. This day-by-day plan is provisional until you choose exact travel dates.
Leave Portland around 7:30 AM for Portland Head Light, roughly a 20-minute drive depending on traffic. Walk through Fort Williams Park for the lighthouse, cliff views, and a quick look at the shoreline; the park itself is generally free, though seasonal parking or donation arrangements may apply. Allow a little extra time if you want to explore beyond the main viewpoint.
From Portland Head Light, drive north to Rockland, allowing about 1 hour 45 minutes to 2 hours. Have lunch in Rockland or pick up something en route, budgeting roughly $15–30 per person for a casual meal. The walk out to Rockland Breakwater Lighthouse is about a mile each way over uneven granite, so wear sturdy shoes and allow 1.5–2 hours; avoid it in high winds or rough weather.
Continue from Rockland to Bass Harbor Head Light, a drive of approximately 2 to 2.5 hours, then allow about 45 minutes for the lighthouse viewpoint and short shoreline paths. The final drive to Bar Harbor takes roughly 1 hour, so this is a full driving day and arrival will likely be in the evening. Check road and parking conditions before setting out, especially for Bass Harbor Head Light, where the access road and small parking area can become congested; if the day starts late, skip the Rockland walk rather than rushing all three stops.
No packing list attached yet.