Once you have completed all of the missions in CJ's San Fierro mission line, you'll get a call from a mysterious stranger who asks to meet with you at a ranch in Tierra Robada. You can reach Tierra Robada by taking the now-accessible Garver Bridge out of San Fierro. Make your way to the ‘?' icon on the map to reach the ranch. Step into the red marker outside of the ranch to get started.
The objective here is to run through a series of checkmarks in under 6 minutes and 30 seconds, otherwise the mission is a failure. There are 35 such checkmarks, and you must hit them all using the Monster Truck that is parked outside. Each checkmark contains a directional arrow that points in the direction where the next checkmark will appear, so pay attention and follow the arrows. If you leave the truck at any time you'll have 10 seconds to return to it before the mission ends. Furthermore, if the truck is destroyed, the mission is a failure.
 Monster Truck |  Checkmark |
The Monster Truck features four-wheel steering which allows you to drive off-road more efficiently while the button is held. The 6 minutes and 30 seconds you are given is plenty of time to run the course, so there isn't much more that can be stated here. Pay attention to the directional arrows and by no means keep to the road. If you can make a beeline for the next checkpoint, do so.
