Slide down the line and when you land, run around behind the car in front of you for grenades. Then head away from the lambent some for cover. Really, this is important for putting distance between you and the Gunker so he doesn't melee you. Once you've cleared them, move ahead a little bit to find out you need to get through the stranded base to see the ship. You'll find out what makes these Stranded so dangerous.
Be careful of the turret between the two doors to the fort. Clear out the ramparts first and then try and land a grenade in the turret bunker. Also be careful because there may be a OneShot up above. Don't get too close because once everything is clear, more enemies will come through the doors, including some Boomers and Butchers. Once the area is cleared, go to the turret in the middle of the bridge (in the toll booth), then go around the right side and just behind it, you'll find a collectable in the pile on the ground.
After that, head through the gate and enjoy the view. You'll actually be safe until you get into the actual fort section. You'll pass a closed red crate on your right and as you continue forward you'll find another but this one is open instead. Go inside, destroy the crate, and pick up the knife on the ground. go back and continue on down the bridge. It's kind of hectic in here but if you just hang back, they shouldn't be too much of a problem. Once you've cleared this room, there is a collectable to be found but it's a little tricky. leave and come back towards this area the way you did originally and on the left, you'll find a balcony sticking out. If you look to the right, you'll find a crimson omen painted on a girder and on the left is a ladder. Go down the ladder and follow the path until you come to a barrier you can mantle over. on the otherside of this barrier (right next to it) are COG tags on the ground. when you come up on the otherside, turn right and continue on your path. ahead, watch for a turret in the back and some tickers. If the tickers get too close, hit the B button to punt them. Climb up the slab of road that just fell into the room to continue.
Just to your left is some cover. Get behind it ASAP because there will soon be a lot of explosions going around. You'll get attacked by some Grenadiers and Boomers. You may want to take out the Grenadiers first because they might otherwise swarm you. Head further along and to the right. You'll head inside to climb down some ladders. Once inside, you'll have to split up. Take the low road.
Make your way up slowly and watch for turrets on the right side. There aren't a whole lot of enemies but they will try and flush you out of your cover with grenades so try and kill them in a timely manner. Watch out for a few grubs popping up out of the ground to your left. Approach the big gate in the back and you'll get to see the ship.
Yeah, that's right, Clayton just called them ladies. He's not shy like his younger brothers. Move to the next area and you'll come to more tickers. They shouldn't be anything too devestating. Run up the broken road to the next area. You'll come under fire from a mortar. Use the empty shipping containers for cover. Wait for a shot, then move. Try not to stay in one area too long because with the mortars alternating, they can pin you down where you are. once you get to the end of the bridge, use your height advantage to take out as many of the locust as you can.
A gas barge will come around and you're told to try and hit it with the mortar. that's actually a little bit on the tough side. Give it a shot though and if you can't, you can still bring it down with small arms. Kill it and then turn around and head down further. Cross the lowest part of the bridge. The tentacles that come through the walls will drop polyps so watch for them. At the end of the section will be a couple of grenadiers. Kill them and exit through the door on the right. Climb up the ladder.
Take a right and rap around the tower. You'll come to a set of stairs that leads back up towards the mortar position but the stairs are broken. To the right side of the stairs, on the ground, is a collectable. Head back around to the left and get back to the bridge road. Head up the road and watch for the OneShot. Grab the LongShot hanging near the truck and use to clear the way. Watch behind you as you progress because some grubs will jump up out of the ground. Head over to the crate and drop the tickers.