Penzance is one of the easiest West Cornwall bases to enjoy without a car because so much of the town works as a walkable loop. The station, harbour, Chapel Street, the promenade and the main visitor spots all fit naturally into a compact plan.
For a car-free weekend, arrive by train, spend one day around the town centre and harbour, then use local buses or a taxi for places like Newlyn, Mousehole or St Michael's Mount. That keeps the logistics manageable while still giving you a proper Cornwall break.
The best version of the trip is unhurried. Book only the things that need a slot, then leave enough time for sea views, coffee and the kind of wandering that makes Penzance feel memorable.