Parking is normally available outside the house, during busy times we have alternative parking available outside Elements of Avebury (opposite) and in the National Trust staff car park a few hundred yards away.
If you are coming by train from London, Swindon is a good stop as the bus station is a short walk from the train station and the number 49 bus will take you to the middle of Avebury (almost outside our door) - £2.90 one way
There is also a taxi rank outside Swindon station, its about £30 to get to Avebury one way.