Load up Uplift reserve and set the difficulty to Heroic
Once the level starts, the general strategy is grab the Warthog, speed past the ghost, 2 choppers and 2 Wraiths. Before entering the tunnel, grab some health on the right if you need it then jump into the ghost. Go through the tunnel the circle round the far right. Cut left and head across the pond, turn right through the gap. Aim for the far right to avoid the turrets, then turn right and boost all the way through.
Follow the path round until you come to a platform with a new ghost and health. Grab both if you need it then boost with your ghost over the railings to the right and keep going boosting past the ghosts and wraiths and choppers. Once under the arch go right and over the bridge. Next building has more health and a fresh ghost. Go up the ramp then go right and follow the right wall all the way round. Head up the ramp and boost past the 2 turrets. More health on the left once you've passed them.
Over the ledge is a giant covenant structure. Boost to the left passed the turret then go all the way round keeping the wall on the left. As you come round the other side, you'll see the Wraith on the right. Make sure you have full health then boost towards the right of it then cut left and boost past. Keep going following the path to the left, turn right at the broken wraith then follow round to the left.
Last open area as you come round the left turn with the covenant barriers on your right you'll see a couple of Wraiths on the left and a rock in the middle. Aim just to the right of the rock, aim for the rocks on the far side and boost in a straight line. As soon as you're over the rocks, turn right and boost off the end.
The below video should hopefully show it better, it's basically the same tactic as
You can pick up health packs along the way (which I highly recommend you do at every opportunity) and doesn't void this achievement. I also recommend grabbing a new ghost every time so it has full armour
One thing I found that when I died, I quickly restarted checkpoint but the achievement didn't pop, nor did restarting the level. When I completed it in one run the achievement popped.
Edit: From ShadowDragon28 - The achievement will still pop even if you restart the level as long as you don't die. If you die, you have to back out and start the level up again from the main menu.