This is about Trent and Donna who are back home and running out of money. So many people are leaving in spaceships that there aren't many jobs and the US is taking all the jewelry-type merchandise because people were trading paper dollars for them. They only have a bit left and decide they'll go back into space and see what jobs are available.
The computer for the hyperdrive is much more sophisticated and therefore Donna (and other people) can use it. They set up the truck again and take off for the planet colonized by the first guy (where Allen and Judy stopped first). When they set down, they listen to the radio bands and hear someone in town saying there looked like a ship that landed that had trouble. Trent replies that they saw a bright object come down and could go see what's up.
When they get to the spaceship, they find a crushed part of it and aliens that have tentacles instead of arms. Through pantomine, Donna is able to convince the mother to bring the injured daughter and the baby back to town and leave the father (small head injury) to be watched by the older son. The doctor gets an xray and the tentacles have little bones in them and the girl has a fracture. She gets a cast and the next day Trent and Donna take them back to their ship.
The night before, after they left the medical center, they stopped at a bar that was still open. The guy who was the first one in a spaceship and the first one there was going on outside the galaxy with his girlfriend and be Adam and Eve. He's sure the US will soon bomb the planet (drop rocks from orbit). Trent and Donna are offered a job -- to take the mail to the French planet because the regular deliveryguy was sick. It pays money, AU money, and they figure they can at least help out.
It's a snowy planet and the red truck stands out. Their contact takes them back to his home which is sort of a giant barrel cactus and starts feeding them dinner when a rock arrives too close. He heads off in his giant white truck and Trent and Donna take off in the pickup which is damaged. They plan to go back to Earth, but end up somewhere they and the computer don't know.
They have to land eventually for air and the first place almost poisoned them. Then they find a planet where the air is okay, there's interesting animals, but all the plants melt rather than burn and the water, even the rain, gives diarrhea and vomiting. They figure out how to get back to Earth, but are again sent somewhere else.
Donna figures out how to do it roughly by hand and they find the Galactic Federation ship and say somebody has to keep the US from bombing all the colonies that are not official US colonies. Donna tells Allen about the program and he looks it over and tells her that it has a module stuck in that if you go anywhere that the US has forbidden (the French planet), the computer will tell the engine to take them 20,000km further than they wanted.
Trent and Donna have a meal with Allen and Judy; Allen offers a way to change things and Trent considers it. Allen also makes a fix to the program and lets the program back out again. Trent and Donna are worried they'll be shot down when they come back to Earth, but all the laser sats have been burned out.