On the Run is the twenty-fourth mission in WorldBuilder.
Immediately select your Buggy and start navigating carefully around the Crabs. The paths you must take are very narrow, so knowledge of the Crabs' movement patterns can help a lot. A word of advice: Crabs will not do anything until they finish moving. If you see a Crab on a tile above or under your current tile moving left or right towards you, immediately drive past. If the Crab is moving up or down a tile, stay back two tiles, then, when it starts approaching from left or right, immediately drive past it.
Grab the plans for the Dirtbuggy at the end of the path. Your Buggy's job is done from here. Go to the right corner of the map where the Gas Station and a pile of bricks are located, and build a Dirtbuggy. If you're going for the Bonus Goal, feel free to pick up the nearby plans for the Defender and the Gas Station.
Treading carefully around the Crabs, go into the labyrinth of trees and grab the plans for the Frog. From here, you can do one of two things: You can assort the scattered green bricks near the goal, or simply drive back, take apart the Gas Station and the Dirtbuggy, and use their parts to build a Frog.
Build a Defender on the far-right section of the map, and disassemble the first Crab you see. Take apart your Defender and rebuild it with a fresh Energy Brick. Start moving downwards towards the other two Crabs and disassemble them. Don't worry if your Defender gets trashed, as you can rebuild it; if a Crab is low on health, a few more hits will do it in. Make sure you disassemble them on or near the pile of green bricks, though, or you will not be able to build the Gas Station on the goal. What's more, you only get one Gas Station plan, so use it wisely.