My solution is just how I did it exactly.
Start Uplift Reserve from the campaign Replay Mission screen.
From the start, flip the warthog, then either:
1) Drive away to somewhere you won't be shot, then wait for the marines to come get in your vehicle, passenger and gunner.
2) After you flip the 'hog just sit and wait for the marines to get in, a little bit more dangerous but gets the job done quicker.
Either way, wait until the passenger gets in, then get him out, and replace his weapon with your Spartan laser.
Now that you have a gunner and a near-invincible passenger, you may proceed.
Still in the same area there will be quite a few enemies, keep you distance but be close enough so the marines notice them, and obliterate them, with a laser and turret, this doesn't take half as long.
There will be a wraith in the same area, and another after you have taken the first one out, still using the same tactics, destroy both wraiths, ghosts and choppers, then move on.
Continue using these tricks in each area and finishing the level will be a snap and will be done in no time.
Be sure to pick up any health packs you may come across if needed.