Central Narva is walkable. The castle, town hall, bastions, churches, and river promenade sit close together, though the streets are broad and not always charming. Kreenholm is farther south; walk if you enjoy industrial cityscapes, otherwise take a local bus or taxi.
For Narva-Jõesuu, use the local bus from Narva or drive. The seaside resort is about 15 kilometres north, close enough for a half-day beach escape in summer.