There are signposts to the away fans car park. Been a few years since I went there but if I remember correctly they take you to the University car park which is just over the bridge from the ground.
Yes. Huge industrial estate best bet. Went years ago when Pride Park just built. Arrived late and city already one down. Told not allowed to smoke or stand in new ground..Got lost and seperated from mates after game in the fog. Found car eventually (hour or so later)as industrial estates all look the same in the fog...well generally actually..yes enjoy your away day Pride Park experience!