To make this a lot easier on me, I took the words from the walk-thru and put it into a table, highlighting the various journal entries you need. It immensely sped things up. Complete credit to the walk-thru author for the words ... my contribution here is simply to order things to make it easier to find as you speed through the house.
I will also note that to get the Speedreader achievement, you need to get Mitten's journal entry, too ... that's number 22. So ... figure out ahead of time where that damned purple ball is in the garage as it's essential to getting this achievement.
1. From the start, open the cabinet, grab the duck, grab the key, and open the front door. Grab folder on table to left for Sam's journal - At the New House.
2. Go upstairs and turn right, open cabinet low to your left and grab the item then put it back for Sam's journal - Hanging Out With the Girls.
3. Continue straight through the door at the end. Examine the lock straight ahead inside the room and enter 0501 as the combination. Examine the picture inside the locker for Sam's journal - There Was Nothing Wrong.
4. Grab the key next to it.
Enter the door on the far side of the room and through the door opposite it in the hallway to go into the bathroom. Pick up the bottle by the tub and put it down for Sam's journal - Dealing With Roots.
5. Go back through the room and downstairs. Turn a sharp right at the base of the stairs and enter the door. Open the closet door just inside to the left and pick up the paper for Sam's journal - First Day of School.
6. Continue down the hall and enter the door on your right at the corner, then through the door on the far side of that room. Go around the partition in the center of the room and look for a panel low on the wall in the corner to your right. Remove the panel and toss it aside, then examine the show flyer for Sam's journal - Adjusting to the Dark.
7. Return back through the previous room and into the hallway, entering the door diagonally to your right as you re-enter the hall (don't hook around the corner to the right) to enter a blue-tinted TV room. Examine the book to the left of the TV for Sam's journal - Big Gold Star.
8. Exit the door you entered for the TV room and go straight ahead down the hall. Enter the door to the left before you reach the curtains, and turn left inside the room to open another door to a closet. Read the letter between the shirts hanging in front of you in the closet - Sam's journal - Default Friends.
9. Exit the closet and the room and turn left in the hallway to reach the curtains. Open the bottom drawer beside the curtains and read the note for Sam's journal - Best Laid Plans.
10. Turn left from the dresser, enter the door, and go down the stairs to the basement. As you enter you'll see two boxes in front of a covered couch. On the back side of the box nearest you, between the boxes, examine the drawing for Sam's journal - It's Different Now.
11. Continue to the right from here (to the right from where you entered) and around the corner to the furnace. To the left, read the letter sitting on the box for Sam's journal - Ship Date.
12. Continue around this direction, behind the wall that the furnace is on, to see a door cracked open. Enter it and examine the scrap on the wall for Sam's journal - I Can Sing.
13. Turn around and exit this room. Enter the room 90 degrees to your right and grab the postcard directly in front of you for Sam's journal - Stick With the Group.
14. Turn left from the postcard and follow the corner around to the right to reach a set of stairs. Turn right into the room at the top of the stairs and read the letter on the desk for Sam's journal - Getting Lonnie.
15. Continue past the desk through the door behind it. Look for a folder on the table to the left of the couch. Close the folder first, and examine the scrap beneath it for Sam's journal - The Nunnery.
16. Turn left from here and head down the hall into the dining room. Look on the far side of the table to your right for a folder. Open the folder, and examine the note first (top), then the slip (bottom) for Sam's journal - A Very Long Phase.
17. Continue to the other end of the table and through the sliding door. You should see a half open door in front of you. Head left around the corner and down the hall. At the far end, in a small alcove down low on the wall to the left of the small table, read the crumpled note for Sam's journal - Dedication.
18. Go left from here when facing the note and around the corner, and enter the door on the left to a laundry room. Go through the far door into a greenhouse-like room, and on the far side to the right of the door, examine the map for Sam's journal - Live Moves On.
19. Turn around and go back through the laundry room into the hallway. Follow the hallway around to the right, then left and into the half-open door to reach the kitchen. Read the story on the table with the blue cup for Sam's journal - Daniel.
20. Go through the door on the right to leave the kitchen and through the next door into the garage. Grab the hat off the bike's handlebars and put it back to get Sam's journal - Just Gone.
21. Grab the milk carton from the recycling bin and back up to the door where you entered by the bike. Look up at the ceiling for a purple ball and throw the milk carton at it to knock it down. Pick up the ball and carry it with you from now on (drop it to open doors and such, and pick it back up after). Leave the garage back through the kitchen. Go left when you reach the hallway and follow it around to the left past the couch you closed the folder by earlier.
Open the door past the couch (pick the ball back up) to reach the entrance area of the house. Open the secret panel to the left of the bookshelves, which are to the right as you enter this area. Go inside and grab the attic key off the box. You'll get Sam's journal - In the Attic when you get the key.
22. Come back out, making sure to grab the ball again. Go up the stairs and down the hall to the right to find an open door with a nerf basketball hoop hanging on it. Aim at the top of the 'backboard' and press to dunk a basket and get the secret journal, Mitten's journal - Meow meow meow.
23. Continue around the hall to the left until you see the attic hatch. Before entering it, go through the door to the right and open the drawer behind the painting easel. Examine the note inside for Sam's journal - Lie to Mom and Dad Situation.
24. Go up into the attic now, and examine the drawing sitting on the green sleeping bag for Sam's Journal - I Said Yes.
25. Then just open the album to the right on the table to end the game and unlock Speedreader if you've managed all of this in under 10 minutes.