You could do even better by putting a good part of the maglev track in a vacuum. This would allow frictionless acceleration and possibly allow you to achieve ludicrous speeds. Possibly subjecting the package to be launched to hypersonic wind fronts for a lesser period of time.The trick would be the transition zone though. Maybe an airlock that's programmed to open at the correct time?
And at that point, the hypersonic payload will literally crash into the thick atmosphere close to the ground. You could launch it along the side of the mountain or from inside a mountain to reduce the density of the atmosphere that you encounter when coming out of vacuum, but you'll still have significant technical challenges.