These Side-Missions are unrelated to the Story-Line, but are still considered SPOILERS for those that do not wish to know its content. These missions are in the order that I received them. Yours may vary depending on where you are traveling.
Pick up Jessica with car trouble on Highway 101 North between
Oxnard & Santa Barbara. You can't miss her. She's waiting in the emergency pull-off. Later on she'll be at the Truck-Stop where you dropped her off
(at 60 Miles Diner), and she'll have a Side-Mission for you.
Pick up the train passenger between
Oxnard & Santa Barbara on Highway 101 North. He's standing by the exit ramp on the divider.
Remember, don't pick up any Hitch-Hikers if you currently have one, or you'll lose the the existing one.
Jessica, the hitcher with the broken down car you picked up earlier
(Road Incident) has a package to deliver to a man in San Jose for this side mission. You have a little over an hour to complete it. So, I went to the warehouse in Santa Barbara, and picked up a load. I did both with plenty of time to spare. The mission pays little. So, you may want to do the same for some extra bucks.
If you didn't pick her up, you won't see her at the diner in Santa Barbara.
You can do this Side Mission, and pick up the next few in close succession, and complete them while you are doing the
"Mysterious Package" Mission, and after. You need a truck that can do at least 75 MPH. The
"Roadside TV's" will be the first one, and is pretty short.
Immediately after the you get a call for the
"Roadside TV's", You'll get a call for this one. You need to make a choice between accepting this one, and canceling the other
(Roadside TV's). You can't do both. I suggest this one because it's more money, and the
"Roadside TV's" has less of a penalty for canceling. You can try to complete both, but when you try to get the Big Red truck, the cops have towed it away, and you won't get the penalty.
You get this Side Mission right around the time you're doing the
"Humanitarian Aid" Mission. Accept it. You have lots of time to finish it, and it's good money.
This Side Mission comes along right after you pick up the
"Majestic-13's" truck. Take it, it's also good money.
This one is very easy. It's on the way to the
"Majestic-13's" drop.
Pick up this Side Mission while doing the
"Getting Acquainted" Mission for some extra money. You need to be
fast & accurate here to complete both on time.
This Side Mission comes as you're heading toward Redding to complete the
"Getting Acquainted" Mission. Take this mission first before the
"To Death Valley" Mission coming up next, for some extra cash.
Pick up the trailer that Martha Washington asked you to do earlier, and take it to Death Valley. You'll need to really make time here. I had to do it twice before I got there with 2 minutes to spare.
On your way back you meet this guy that needs to get to Death Valley for an interview.
Trixy gives you some information on a job offer. You'll meet her a few times during the course of the game. I always talk with her, and pick her up when I see her, as she has lots of information, and getting jobs for some good cash.
Take Trixy's advice about Jimmy having some work for you. Easy bucks if you ask me.
Mr. Fernandez calls you to pick a trailer of Children's Games.
After Story-Line missions.
At some point after the Story-Line is completed Trixy called me as I was approaching the G.G. Bridge, and asked me to pick her up. When you get to the opposite base of the bridge take the first exit into the parking lot. Trixy will be on the left by the parking lot exit
(not shown in video). Trixy tells you about getting a good long distance job paying good money, and she'll call me later. In this mission Trixy gives you lots of time to drop her off at her destination, and will keep you
company 
, while you pick up some loads on the way. I did three before I dropped her off.