Galápagos needs its own plan within an Ecuador trip. A land-based stay gives you a town, independent evenings and a selection of outings. A cruise ties the experience to a particular vessel and route. Begin with that choice, then decide which islands and visitor sites justify the journey.
For a first land-based visit, five to seven nights is our starting suggestion, not a minimum rule. One base can be more rewarding than a short stay split across several islands. Santa Cruz, San Cristóbal and Isabela have different town settings and connections; changing islands uses time that would otherwise be available for a walk or marine outing.
The regional guide includes a worked seven-night example and separates mainland flights, airport transfers, island changes and entry procedures. Connect that island plan with the mainland calendar before booking international travel, particularly when the final departure depends on more than one transport leg.