Sounds like it would be a one-way trip.
I suppose they could send a ship large enough to hold a second propulsion laser that would then be left at the destination. That way the remaining bit could be sent back. Once the laser’s on site, then larger craft could shuttle back and forth.
Maybe eventually set up nuke powered way points that could be used to send craft in any direction at strategic points in the solar system. Just rendezvous with a way point and have it’s laser shoot you to the next leg of the journey.