Then run an all day service doing the orange route, running non stop from the North P&R and all stops through Team Valley. It's quick to Newcastle, but at the same time you have a counter flow towards Team Valley which makes it more sustainable in the long run.
It's how a lot of the successful P&R's in York run, especially Monks Cross and the Designer Village.
It's much better than the next junction back, then having the use the 21 or X21 which are a chore of a route.