With mountains and tunnels you can have a much longer runway. Maybe Musk's SpaceX and Boring companies can have a joint venture. With Everest at about 9000m and

With mountains and tunnels you can have a much longer runway. Maybe Musk's SpaceX and Boring companies can have a joint venture. With Everest at about 9000m and the deepest mine at 4000m that would give you 13000 meters. Maybe you could dig deeper or curve the track for an even greater launch distance and less peak acceleration.