After you have fought your way through the hoards of zombies on the balconies and in the farms using your Chainsaw Blaster, a tractor will open up the path ahead to the rest of the farm. Simply shoot the tracotor with your CHainsaw Blaster to open up the path ahead. When it's all clear, proceed through the hole in the fence to reach the next area of the level. Round the corner to the left and saw through the thin wood of the shed to your right to find plenty of coins for the upcoming store and a lollipop. Exit the shed as Nick makes a morbid comment about Juliet's sister and visit the store on the other side of the shed. The game will certainly begin to ramp up in difficulty form this point onwards, so if you haven't been investing too much in Juliet's character progression or moveset, now would be a great time to start. Additional combos, such as the Maelstrom Spin or the Chainsaw Chain, can be great assets for stunning or slicing enemies as they come towards you. Other upgrades, like increased health, strength, or lottery cards, can never hurt either.
Leave the store when you're done with it and head up the stairs to your left. When you reach the top of the steps, you will be able to see Rosalind driving the bus aimlessly around in the field below. Time to go reunite with your sister. Scale the sandbags to your right by hitting the B or the O button, depending on your console choice, and drop down into the field below. This will trigger a cutscene to begin. Rosalind will be in trouble again. Her bus is simply covered in zombies, but Juliet's presence will distract them. The zombies will leave the confines of the bus and come after you. Luckily, there will only be three zombies that you will have to kill in this section. Take them out. It should be easy.
Unfortunately, you will now have to kill flying zombies, just like the ones who assaulted you in the boss battle against Yumil. They will fly around the arena on spurts of blood that jet out from their severed legs. You will have to kill three of these enemies before the path ahead opens up to you. Note that you can technically hit and kill these enemies using your chainsaw. The process will be much like it is for combating enemies on the ground, except, naturally, for the fact that the enemies in the air are much harder to accurately hit. Instead, the best way to kill airborne enemies is to target them with your Chainsaw Blaster. Snap the lock on to the flying enemies and pull the trigger repeatedly until they're nothing but a fine mist. This will send Rosalind's bus careening further on into the level, opening a path through a wall ahead for you to go through when you're ready. First, though, Juliet will receive another call from her mom on her convenient chainsaw mounted phone. She'll tell you that you'll never believe what Rosalind just bought; a bus! Go figure. Run through the path opened up ahead. You will come upon a field of zombie cows. You don't have to kill the zombie cows, but if you want to, you totally can. They won't fight back too often, but note that when they do, their charge attacks have the power and the force to knock you to the ground easily. Killing the cows might be kind of inhumane, but you'll get plenty of bonus coins out of it, so hey... might as well go for it. The coins will always prove helpful when visiting the shop, and you'll need all of them you can get it you are trying to fully upgrade Juliet's stats in one playthrough; this ambition is certainly possible, but it'll be very tough.
When you've tired of playing with the cows, or if you have simply decided to move onwards without bothering with them, follow the path up the hill to reach the next arena and the next checkpoint.