Congratulations on your son getting a place at LG
I know there is a train service that runs between Reading station and Langley station, followed by approx 15min walk to LG. If you check the train schedules you can get an idea on journey times and price involved. The councils do not provide any form of transportation to OOC schools, and only provide a service if the school your child attends is more than 3miles away, and is the school the council have offered you as an in county place.
As to the the difference one is a boys only and the other co-ed, by visiting the school, you can get a a real feel for it. I know my DH was very impressed with LG.