The Trucking odd jobs open up after you finish the mission Tanker Commander for Catalina. There are 8 levels and each one starts at the RS Haul Depot in Flint County (truck icon on your map). There are three types of jobs: ones where you must drive to a location within a certain amount of time, ones where you must take no damage and ones where you must outrun the law. Except for the law ones, the money listed for the others is the max amount possible.
If the trailer detaches from the cab, you have 60 seconds to reattach it or you fail the mission. You also have a limited amount of time to return to your cab should you leave it. Try to plan your route beforehand (the yellow blip won't appear on your radar until you enter the truck). When you finish the 8 missions below, RS Haul will become an asset and can generate up to $2,000.
REWARD - $1,000
The first delivery is located somewhere in the western area of Red County in Los Santos. You have about 2 hours (2 minutes in the game) to make the delivery. If you make it to the designated location in time, then you get the full $1,000. If the time goes past what is told to you, then you will gradually start losing money off of that $1,000, so speed is an issue.
REWARD - $1,500
You must deliver fragile goods to some place in northern Los Santos (I had Montgomery). Avoid any dings with other vehicles, since this will lower the money that you receive at the end. There is also a damage meter on the screen that you must be aware of; if it empties, you fail. You are not timed, so take your time and plan your route beforehand.
REWARD - $2,000
This is your first trucking mission with the law on your tail. As soon as you drive out of the RS Haul lot, you will get three stars. There's no damage meter or time limit, but the cops will continually try to deattach the trailer from your truck. As long as you keep moving, no choppers will bother you.
REWARD - $3,000
This is solely another timed mission. You have about 5 minutes to make the delivery to Angel Pine or Shady Creek. Either way, I suggest taking the freeway to avoid the biggest amounts of problems. This is only a timed mission, so you don't need to worry about damage.
REWARD - $4,000
The missions starting from here start to get harder simply because of the fact that you must carry the goods to farther locations. This is another mission where you must watch how you drive since you're carrying fragile goods. The location will probably be someplace on the east side of San Fierro, so make sure to only follow the major roads to avoid any major damage.
REWARD - $5,000
This is another mission where you must fight off the law while delivering illegal goods. You'll be delivering to a place in the southern Badlands, so the freeway is a quick and easy way to get there. You only have to take on a three star wanted level.
REWARD - $7,000
This is a mission that incorporates both the timed aspect and the damage aspect from the trucking missions so far. You'll have around 6 minutes to deliver the load to some place in the desert west of Las Venturas. Plan your route on your map before you start driving and drive safely and quickly to get the load delivered.
REWARD - $10,000
Welcome to hell! This mission is hard. As soon as you drive out of the lot, you will receive a four star wanted level! What makes it damn hard is the fact that your destination is someplace on the east side of Las Venturas. Before you drive out of the depot, look at your map and plan your route carefully. Enforcers join the fray with the more aggressive cops, so you will have your hands full.
An easy way to complete this mission without too much hassle from the law is to use the train tracks to get to Las Venturas. As soon as you get out of the lot, go straight and turn right onto the tracks whenever you see them. You can follow the tracks to Las Venturas while avoiding a large portion of the law.