Well, made my first trip to DSA by road since I attended the last Finningley airshow. Took about 50 minutes as expected from west Sheffield at midday.
I think coming from the west of Sheffield (or Sheffield/Rotherham in general) your probably better taking the M18 via the M1 route. If you come off at junction 3 (M18) it's pretty plain sailing from there on.
I wouldn't have advised using the back roads south of Doncaster and Rotherham.