Johnstown is a small city and most of its main attractions are within a manageable area, but a car is useful given the geography — the city is spread across a valley floor and several hillside boroughs, and some key sites are well outside downtown.
On foot, the downtown core around the Johnstown Flood Museum, the Stone Bridge, and Cambria City is walkable. The distances are not large, but the terrain can be hilly and sidewalks outside the centre are inconsistent.
The Johnstown Inclined Plane functions as public transit as well as a tourist attraction, connecting downtown with the borough of Westmont on Yoder Hill. It runs regularly and is a practical way to reach the hilltop if you're staying in that area.
By car is the best way to reach the Johnstown Flood National Memorial near St. Michael (about 16 km northeast of downtown), the Grandview Cemetery on Millcreek Road, and the surrounding state parks. Parking downtown is easy and generally free or inexpensive.
Cambria County Transit operates local bus routes in the city and surrounding area, but service is limited in frequency and coverage. Useful for basic trips within the city but not reliable for reaching outlying attractions.