The historic centre and the foot of Citadel Hill are easily walkable. The funicular from the base of the hill to the citadel runs throughout the day and takes the work out of the climb; the alternative is a steep zig-zag footpath through the nature reserve.
For Hunedoara and Corvin Castle, local buses and minibuses (maxi-taxi) run from the bus station roughly every half hour. Taxis are cheap; rideshare apps work intermittently. A rental car opens up the Roman sites, the arboretum and the Apuseni foothills.