This is a much improved version of the mission. I removed the heavy weather because my system can't handle it; something to add if you have the horsepower. This mission uses triggers to extend the time of the mission and keep the action going.
The goal is to create a living world, and keep it going. There is no limit to how long you can keep it going. For example, place a unit that travels at 10mi/hr, and after it reaches 10 miles, trigger another unit that does the exact same thing. Do that 4 times, and you've got a 4hr mission.
I use my ground units that are moving up the coast to trigger more Red and Blue units which are "Late Activation" in the mission editor. Feel free to expand on this mission.