Stepping back a bit to make this possible...
- The rogue celestial objects are not planets. They are asteroids.
- The "Planet Walkers" live inside this asteroid.
- The lack of atmosphere or magnetic fields on asteroids mean that they can accrue a large electrical charge from the solar wind.
- Creative use of the electrical phenomena around asteroids will put some space between the shenanigans of the planet walkers and cruel Newtonian physics, and make for fun and engaging fiction.
"For example, understanding the electrical environment around an
asteroid could help identify locations where astronauts can safely
make first contact with the object," said co-author William Farrell of
NASA's Goddard Space Flight Center in Greenbelt, Maryland. "If an
astronaut is tethered to a spacecraft that is in sunlight and
positively charged, and touches a negatively charged asteroid surface
in shadow, there could be an unexpected current flow between the two
systems upon contact. We simply can't speculate on the nature of that
current without this model."
The electrical charge on asteroids can produce attraction or repulsion through empty space, and be strong enough to overcome the pull of gravity. One can even see this on earth, where static electricity can pull an object up off the ground. In dry airless space static charges can become very large.
NASA has a scheme for an "E-glider" - a spacecraft which makes use of these electrostatic forces around asteroids to maneuver.
So in this scenario, the Planet Walkers manipulate electrostatic forces as artificial gravity on their low-mass asteroid. These same electrostatic forces are what allows a near miss between their home and their new destination - as they closely approach they repel each other. The Planet Walkers use the near miss to make their jump and by altering the electrical charge on their own bodies, are reeled in by the departing lonely object.