For a start the RLIF needs to get together and commission RL's answer to 'The World In Union'.
All international governing bodies (That can afford to) should put money in a big pot. All international game marketing should be commissioned by the RLIF.
Once the promotion is correct and fans have been attracted to the game cut ticket prices (or have more double headers) and perhaps do 'England Shirt and a Final Ticket' offers (get the shirt now and be sent the ticket closer to the date of the game).
This should eventually create a Critical Mass and demand would be higher for tickets in the future, prices can go up... more money can be spent on marketing and improving the game abroad as well as at home.
That would mean more teams, more excitement and a huge atmosphere at the grounds.
Location of the games will always have an effect, so play the games that struggle to gain attendance and the finals in the middle of the heartlands. Simi-finals and other large internationals should be played just outside the heartlands or in London (due to large foreign born population)
..... Shame it wont happen......