The A38 runs right through the middle of the Hillfort although you wouldn't know it unless you had an O/S map with you! Parking is difficult on this busy road but I managed to park near the Tytherington turn off. Walking towards Alveston you come to a national speed limit sign (black line through a white circle). If you look to your left, over the stone wall, you can just about make out the remains of the curving bank - heavily ploughed out. This was the only part of the fort that is easily accessible. I can't comment on the preservation of the rest of the Hillfort.
According to George Witts in c1882, "There is a local tradition that 'in the time of the wars' blood ran down Abbey Lane like water, and many people are still afraid to go down the lane at night! "
"The views from this position are very extensive, including the river Severn for many miles, Stinchcomb Hill, Haresfield Beacon, Bredon Hill, the Malvern Hills, May Hill, Dean Forest, Lydney, Chepstow, &c. The ancient Ridge way runs through the centre of the camp. "
As for its name:
[It] is in a piece of ground called the Abby, as Sir Robert Atkyns thinks from an old house near it which formerly belonged to an Abby. It is about a mile from Alveston, and near the eleven mile stone in the road from Bristol to Gloucester. Its dimensions are about two hundred and forty yards from east to west, and about three hundred and forty from north to south. It is much mutilated by the plough and other things. It may be seen from Oldbury, Old Sodbury, and Westridge. Most probably also from Dyrham, Horton and Drakestone.
From 'An Account of a Chain of ancient Fortresses' by Thomas Baker - In Archaeologia 19 (Jan 1821).