Heffer looks through his video clip and sees attractions such as the world's largest slice of processed cheese, the toe jam towers of Detroit, Purvis the world's fattest rattlesnake, and Flem Rock. When Rocko realizes what Heffer has just said, they watch it on television and find out that the place is about to be demolished on Friday, so Heffer suggests that he and Rocko should go on a road trip to see Flem Rock. Rocko is initially skeptical, but then agrees after Heffer makes an impassioned speech. The two ride a motorcycle sidecar and Heffer puts on bagpipe music.
As they approach a desert, they find that they are 500 miles away from Flem Rock and make a left turn. When they go around various of places, Heffer finally concedes the fact that he doesn't know where they are going. So the two decide to ask for directions and come across a farmer, who gives them comprehensive directions. He spends all day keeping the two waiting by telling them his story and Rocko and Heffer, no longer patient, decide to ride away, leaving the garrulous farmer standing alone during the night.
When the two friends continue riding, they approach Bait's Motel and decide to go somewhere else. So they go to No Tell Motel and when they wake up the next morning, they are back on the road with the bagpipe music still playing due to the tape being stuck inside the radio player and the volume knob coming off. When the music gets into Rocko's head, he finally becomes irritated of it and stops the car to pull off a parking meter and whacks at the radio player. As Rocko tries to destroy the radio player, Heffer goes to Sausage Shanty, a diner, to eat. By the time Rocko finally stops the incessant music (in which the tape comes out of the radio player without a scratch), he has also destroyed the entire motorcycle sidecar in the process as well. Rocko joins Heffer at the diner and tells him the bad news. Suddenly, Heffer becomes the first customer to ever devour the Knockwurst Nightmare Platter (which are pig intestines) and win a box of Rice-O-Roony, a copy of the home game, and a weenie mobile.
Rocko and Heffer are back on the road riding the weenie mobile, but the vehicle runs out of gas and some intimidating bikers (led by a horse with Stinkweed, Spike, Lefty, and a goat) come around to fix it. Rocko and Heffer hop back inside the weenie mobile and Rocko presses the nitro button to speed the vehicle up. They make it to Flem Rock to find that it's smaller than it was shown on TV and they meet Yukon Sheldon (the only person to have climbed the rock). After the final eruption, the rock is leveled by a steamroller and a Chokey Chicken restaurant is dropped on the parking lot via a crane.
As the two friends eats at the restaurant, Rocko tells Heffer that it's good discovering America on the back roads and they should do it again. Heffer suggests that the two should go to other exhibits, which causes Rocko to become overwhelmed.
Jeff "Swampy" Marsh, a storyboard writer, says that the "biker horse" who fixed the Wienermobile originally said "Retorqued your johnson rods." The censors forced the creators to alter the lines to "...retorqued your curtain rods..." due to the sexual innuendo in the original statement (both "johnson" and "rod" are slang for male genitalia). Marsh and the other crew disagreed, believing that children would not comprehend the meaning of "johnson." Marsh describes the particular "biker horse" as a caricature of himself and the other motorcyclists as caricatures of Dan Povenmire, Marsh's wife, Doug Lawrence, and Robert Skull. The original broadcast of "Road Rash" featured a scene in which Rocko and Heffer stop at what is suggested to be a love hotel (the "No-Tell Motel") advertising "hourly rates" and ask the horse desk clerk for a room, who infers the two will be engaging in intercourse: "All night? [whistles] Wheeeooo! Okay." In all Nickelodeon reruns, it only show a still image of the hotel briefly before cutting to the next scene.