I think that they could get away with 4 instead of 6.
OR
They could play 2 of the pre-season games in "alternative" sites. Like, A CHL arena or an AHL arena for the affiliates of the teams. This would save season ticket buyers a little.
Also, the Rookie showcases should be part of the greater pre-season. This makes the process more like baseball's spring training, where the games get increasingly "real" as you get closer to the first game of the regular season.