Approx. 174 miles, 3 hours.
Join M25 leaving at Junction 15. Join M4, leave J19. Join M32, leave J2.
Join B4058 then B4469. Turn left into Downend Road, (see map below), turn right onto Alton Road. There is a fair amount of street parking available away from the ground.
Just try and avoid the city centre and one of the world's worst one way systems!
The ground's at Filton Avenue and north of the town centre.