Washington in the fall trades the summer's heat and thunderstorms for a city that's genuinely pleasant to walk across, which matters more here than in most places — this is a town built at a pedestrian scale that August makes miserable and October makes ideal. The version of that worth planning a couples' weekend around isn't the Mall, though; it's Georgetown's canal towpath and the walled formal gardens above it, both close together and both built for slow walking rather than checklist sightseeing.
This plan skips the monuments and the free-timed-entry Smithsonians — worth doing, but built for a different trip — for a weekend of quieter, more deliberate stops: a canal path shaded by turning trees, a garden that closes at six and rewards arriving near then, and, if you want a full day away from the city, the drive up to Shenandoah's Skyline Drive.
Good to knowGeorgetown has no Metro stop of its own. It's walkable from Foggy Bottom or a short ride on the DC Circulator bus — worth knowing before you plan a car-free weekend around it.
How to use thisEach day has one anchor, an easy backup, and an eat/rest note. Dumbarton Oaks' garden tickets are sold online only, not at the gate, so buy them before you arrive rather than showing up and hoping. If Day 3 goes to Shenandoah, it's a real drive — budget the full day and check NPS's fall color report the week of your trip, since the park's elevation range means color arrives on the ridge well before it does in the valley below.