G forces are less problematic when launching bulk materials (fuel, air, water, foodstuffs, metals - as I see the project proposal suggests). If you're 'catching' the payload at the other end, you can make the launch vehicle very dumb. Even more so if you can leave your engine at home and still use it (see also "ablative laser propulsion").

Radial forces on the launch platform itself are more of a concern. You have to stop it from tearing itself apart while it overcomes friction/drag and reaches escape velocity.