Park and Ride works for the Stadium of Light as it's in an awkward place in a city that's far far far less developed than Newcastle in terms of infrastructure.
The problem with having a P&R from the Metrocentre (the old P&R failing too) is that around key dates the traffic around the Metrocentre is horrific to get to at the best of times and you may as well drive into Newcastle and use the car parks in the City or preferably, a Metro station (Callerton for example)
RE: Go North East