For those who rely on public transport. Wessex Connect bus service route 625 runs from Bristol Parkway Station to the Fox at Easter Compton, see
http://www.southglos.gov.uk/NR/rdonl.../PTE070687.pdf
Pilning Station is not far from Easter Compton, but I cannot see on Google Earth whether there is a footpath along the road, perhaps someone local can advise