There is also a lot more to marketing than just offering good deals (not saying you're suggesting that, but needs a mention). If people don't know about these offers, it won't make a difference. And if you're preaching to the converted, you could end up losing money.
Considering the Midlands' reasonable proximity to the heartlands it's a reasonable risk to have one game there, and the bigger it is the more it should appeal to people in the Midlands who I'm sure include many former northern residents who'd be fans of RL. Ricoh Arena's management is open to hosting all manner of events so they might come forward with a great offer and it's a lot smaller capacity than new venues in London are. I do think that with more countries than 1995, having one more game outside the heartlands than there was then would be a way to show some modest growth in the sport's national appeal.
Part of the marketing has to be building up the World Cup as the pinnacle of the game, like they are in other sports. Then combine that with great ticket offers to get fans excited about seeing it.