It's before you get to the BOC car dealer.
Going out of town along Hyde Road, immediately after the Ardwick Bus depot on the left hand side, there is a long old brick wall with a new brick section about half way along. This was the site of the City Gates pub where (I believe) the team used to change for games. Just behind the wall is a railway line and the old Hyde Road ground was just behind that.
Just past the City Gates is a left turn for Bennett Street, which takes you under the railway bridge and immediately to your left would have been the 'popular side' the Bennett Street end. The area is a container park now, but there are 2 gates with cobbled surfaces. I think that one of gates was the actual entrance to the Bennett Street end.
If you stay on Hyde Road (i.e. don't turn left onto Bennett Street) you'll see a new Medical Centre on the left and I think that was the site of West Gorton St Marks. Further along Hyde Road on the left is Gorton Park, where one of the clubs that became City played.
Gary James' book is the definitive source for all this (I need to dig out my copy and reread it).