Local travel by bus and train
The start and finish at the Wey Valley school is on a bus route from Weymouth and Dorchester, and about 5 to 10 minutes walk from Upwey station.
This webpage gives a link to the local bus time tables.
The number 10 bus (see map) runs four times an hour from Dorchester (the bus stops on the road main outside the station, not in the station itself) to Upwey and the Wey Valley School, and there are two trains an hour from Dorchester South to Upwey station.
It is easy to take a train from further out on the Waterloo line on the day of the event. There are two trains an hour from Bournemouth to Upwey, and the journey takes about 55 minutes. You'd need to get up early, but it's feasible to get a train from Waterloo on the morning of the event. See the National Rail website for up-to-date details of times and possible disruptions. There is no engineering work planned over the Bank Holiday that might affect travel to the event.