å gå = 'to walk', but also to go or leave if you do so on foot - even if it's just out the door.
å dra = 'to go/leave' (you can use the prepositions 'til' and 'fra' to make it clearer).
å reise = 'to travel', but there's the same overlap in Norwegian between 'dra' and 'reise' as there is in English between 'going' and 'travelling' to X.
å spasere = 'to walk', but leisurely so. Walking for the sake of walking, rather than as a means of getting somewhere in particular.