Depends on the room really.
You can get past the first 3 zombies just by pathing correctly. Guy at the end can be a pain in the ass, some people are good at getting up without him doing shit but I don't know how to do it consistently so i'll usually pop him.
First dog room you just hug the right wall then move slightly left to dodge the dog and jump down, it's really easy.
Second dog room with the bridge is just fucked, worst room in the game. Pop the first zombie, dodge the dog as you run onto the bridge, hug the right and PRAY that the zombie lets you run past him then PRAY that the dogs don't hit you, a bit of a zig-zag can help but also fuck you over.
You can run past all the zombies after that. When you get to the dark room after the elevator up you can run past everything by just running right of the center pillar and then bee-lining it to the stairs. Dodge the licker by hugging the left and hope he does his big swing because if he toungues there's a good chance he'll chase and hit you.
Next dog room is easy, just hug the left all the way around. Parking lot go right, pop the guy in the white coat, pop the guy who walks to the very right and go right past. The licker after that depends on who you're playing. Hunk can deagle it once (do it while hugging the wall when you're at the door on the left) and then run past, but it can be tight.
To dodge Mr X just hug the left wall all the way around but make sure you get around fast enough or he might still get you. Next zombies can be a bit RNG, you can generally run past them all no trouble, run on the left side of the desk in the office. When you go through the second red door run through it more towards the right becausse the zombie there can be a bitch.
Pop the guy on the right next o the key door in the main hall, take the right side of the desks and pop the one guy there. Dealing with the licker after that depends on the character. It can be alright to take the hit for most characters etc...