Arcadia - Bioshock
Upon entering the Tea Garden area, turn left and follow the stone path to an audio diary (Seeing Ghosts). It's on the grass, near the chairs and table. Proceed through the door to the left of this area, pick up the audio diary (Big Night Out), which is next to the bench straight ahead. Follow the stone path over to a couple of chairs, an audio diary (Mass Producing ADAM) is on the ground by these chairs.
To The Metro Station
Continue down the stone path, proceed through the wooden door that you eventually come to. Here, you will likely have your first encounter with a Houdini Splicer. Be sure to take as many pictures as you can of this Splicer to make things easier for yourself through the acquired research bonuses. Grenade Launcher ammo can be found here, it would be wise to keep this ammo for a Big Daddy encounter.
Follow the Splicer up the stairs, in this area you will face him. As you can probably tell, Houdini Splicer's are going to be quite the nuisance. From this point on, they appear in all subsequent levels, you'd better get used to dealing with them. There's an audio diary (Arcadia Closed) on the table next to the Gene Bank machine. Locate the door on the second level, travel along the walkway and enter the next area. Use Electro Bolt on the door control to the left, this room contains ammo for various guns. Drop down through the opening in the floor to the level below. Locate the door on this level and proceed through it.
Up the stairs, turn right and approach the U-Invent machine in the corner there. U-Invent machines allow you to use colleted items to create ammo. This is a good way to get ammunition if you are low on money, as you are sure to collect many ingredients while playing. A Big Daddy and Little Sister can likely be found lurking in this part of Arcadia. As usual, if a Little Sister is not with the Big Daddy, follow him to one of the circular vents along the wall. If you've been rescuing all of the Little Sisters up to now, you should be receiving your next gift from Tenenbaum with the rescuing of this one.
There is a Gatherer's Garden machine in Arcadia Glens, too. It's just outside of the WaterFall Grottos door. Speaking of WaterFall Grottos, if you have been collecting audio diaries, that is where you should be heading next. On the other hand, if you don't care for audio diaries, there is no need to go in here yet, though you can still get some ammo out of it.
Upon entering WaterFall Grottos, turn right (or left, depending on the door you used to enter), one audio diary (The Market is Patient) can be found on the bench. A U-Invent machine on the left side of this room holds some free Heat-Seeking RPGs for your Grenade Launcher, these would prove useful against a Big Daddy. Several Turrets and a Security Camera occupy the area at the bottom of the stairs. Make your way down the wooden walkway. Once you have traversed the entire walkway and are standing below some stairs, move forward and retrieve the audio diary (Offer A Better Product). From here, turn right, approach the storage crate and pick up the audio diary (Early Tests Promising). Head up the stairs next to the water wheel. At the top of the stairs, hit the door control with Electro Bolt to open the door. You'll find an audio diary (Heroes and Criminals) and some ammunition inside of this room.
The Rolling Hills area can be reached from Arcadia Glens. RPG Turret to your left as soon as you enter, watch out for that. Just behind the turret, on a bench, look for an audio diary (Shouldn't Have Come). You'll find the second Big Daddy of Arcadia in Rolling Hills, just be sure that he has a Little Sister with him, then start attacking. Go down the set of stairs to the right, at the bottom turn left and move towards the cave. Pick up the audio diary (The Saturnine) on the ground by the opening of the cave. You cannot enter the Metro Station until you save the forest. Your new task is to find and speak to Julie Langford.
Step through the doorway that has the "Langford Laboratories" sign above it. Julie requests that you find a specimen of Rosa gallica. She tells you that it can be found in WaterFall Grottos. You are unable to proceed any further. Backtrack to Arcadia Glens and enter WaterFall Grottos. A group of Thuggish Splicers surround a corpse by the entrance, kill all of the Splicers and take the "Security Evasion" Physical Tonic on the ground by the corpse. A sample of Rosa gallica can be found by the water wheel on the lower level of WaterFall Grottos.
With the Rosa gallica specimen, return to the Langford Laboratories entrance and send the rose through the Pneumo Tube. The door opens. Pick up the "Hacking Expert" Engineering Tonic that's on the desk up ahead. There's an audio diary (What Won't They Steal?) to the right of the desk. Step through the door on the right side of this room. An audio diary (Teaching An Old Hound) can be found on the table to your left. Make your way to Julie's location. Unfortunately, you are not able to speak with her, as Ryan Andrews promptly kills her. Luckily, before her death, Julie managed to print the code for the wall safe on the window. That's all we needed from her, really. Search her corpse and remove the audio diary (Lazarus Vector).
To The Farmer's Market
Take the Chemical Thrower that's on the table in the middle of this room. This weapon will be of great use to you. Approach the painting of the flower, and move it to reveal the wall safe. The combination is printed on the window right behind you, 9457. Inside the wall safe is a Market Key, an audio diary (Lazarus Vector Formula) and a bit money.
Farmer's Market is your next destination. You must find the ingredients and invent the Lazarus Vector. Farmer's Market can be reached from the Arcadia Glens, though there are some audio diaries that must be collected on the way out. Once you are out of Rolling Hills, from the entrance, turn left and enter Tree Farm. An audio diary (Arcadia and Oxygen) is leaning against the crate straight across from the entrance door. As you first walk under the archway with the giant "Farmer's Market" sign, turn left. A Power To The People weapon upgrade station is on the wall here. At the top of the stairs leading down to the Farmer's Market entrance, look for an audio diary (Maternal Instinct). Head down the stairs and enter Farmer's Market.