"periodically fire one laden [rock] with electronics/optics/quantumics at the target star at near light speed and receive its transmissions for recon" These wo

"periodically fire one laden [rock] with electronics/optics/quantumics at the target star at near light speed and receive its transmissions for recon" These would act as space weather beacons, forming some kind of illuminated space (high)way. An interesting idea! As for the rogue planets, although I envision humans having some use for them, I doubt it will be for interstellar travel the way you describe.