Its always felt like a better near term way to boost around is just use massive (literally) platforms that have large installations of solar, batteries and electric thrusters. Have enough ballast that its orbit is only going to change a small amount when throwing something. Then you just keep thrusting until you are back where you were.

Electric thrusters are getting huge specific impulse improvements and the future seems to be pretty bright for them. We can trade time for efficiency essentially.

For interplanetary transit, just keep the platform running a circuit between the planet and earth. It's going to be way easier to hit your entry without getting into an unrecoverable situation.