Parking is either along the road at Rosevine (free but can get a bit busy in August) or in the pay & display car park by the New Rd in Portscatho (lovely walk along the cliffs around 500 yards). Both are a short walk to the hut. Please be aware that wheelchair access, whilst not impossible, can be difficult. You are welcome to drop people/beach gear off on the slipway at the bottom of the rosevine road and then park afterwards, but please no parking in the surrounding fields.
Buses from Truro are on the 550 Western Greyhound and service Portscatho daily. See here