Explore Silver City and Ride the power lines are optional missions in Going Commando that take place in the Silver City, Boldan. Ratchet and Clank chose to explore the city to search for anything of value, and eventually found a set of power lines that provided transport around the city. The two used the Grind Boots along the power lines, and at the end of them, they encountered Slim Cognito once again, selling weapon mods.
It is possible to reach the Insomniac Museum garage along the power lines, and through a glitch, enter the garage, and thus, access the teleporter to the Museum.
To begin the mission, from the main entrance, head straight up to the elevator by a tower, then climb the ladder past that, and jump on the power line, beginning a Grind Boots segment. Along the first few areas, jump left and right as needed to avoid the electricity generated from the electric transponders, and avoid them as well at the end of each cable. At the end of these power lines, jump across to the yellow railing, and then jump to the power line again to continue (make sure you jump, as you will otherwise fall to your death at this point). Continue along the power lines and jump across to the construction site, grind across the beams, then jump again to the next set of power lines. Once again, continue to dodge transponders through the rest of the power lines, jump across the gap to the last construction site, and reach your destination.
You will eventually reach an island with another Slim Cognito mods shop. Purchase mods for weapons you are currently using (such as the Lava Gun, Bouncer, Minirocket Tube, Spiderbot Glove, Plasma Coil or Hoverbomb Gun) while you are here, then take the teleporter inside the building back to your ship.