Hacksaw's notes mentions that aside from his own tools (which are given to you with the notes), he also needs you to track down at least two other common items. You can find these anywhere you normally expect in the wasteland, or even buy them. They're pretty common.

Head northwest from Springvale - towards the hill that vault 101 is buried in, and near where the overpass between Springvale/Bigtown is. Stand on the top of the hills, and look for power-lines. Follow them.

There's a sewer waystation not too far from Megaton. Check the inside thoroughly after taking care of the roaches and the scorpion - there may be another clue as to where you might find those valves.

Hacksaw's pretty clear about where to find these in his note. Check the area thoroughly.

All of these can be found in Springvale. Check each ruined house THOROUGHLY. They are ALL outside - you do NOT need to go into any buildings (like Silver's house) to find them!

Explore the school AND what's under it. Bring some lockpicks.

I recommend you pay the Doctor a visit next time you're near Big Town.

Buy these at the Caravan Radio.
For the clutter/static decoration only, buying this does NOT automatically show the decoration. Exit the barter menu, and reactivate the radio. You should have an option to enable static decoration. You can switch this on or off whenever you like at the radio.
The bobblehead stand works pretty much exactly as you'd expect in the base game.
The snowglobes are a different story. This means you have to speak to Jane to sell the snowglobes to Mr. House. Once you have sold the snowglobes, and they become visible in the Lucky 38 Suite, then activate the snowglobe stand again, and it should update and display any snowglobes you've found. For DLC snowglobes, things work slightly differently. All you have to do is complete the DLC main quest, and then activate the snowglobe stand. Again, it should update and display the snowglobes for any DLC for which you have completed the main quest.

Some weirdo is messing around in Jury Street Station. Explore the station and tunnels thoroughly, and find the guy who...isn't like the others. He's doing something wacky science with molerats.

For seeds, go pay the Rivet City science lab a visit. Remember that TTW adds a small room just off from the science lab for hydroponics - explore it thoroughly!
For what to grow your plants in? Well, go pay Harold a visit, and watch your feet!

1.) Check out the Wheaton Armory. When you can get into the room with the goodies, look for a pointer towards the next location.
2.) The note pretty much tells you where to head next. Here's a hint: Remember that the hardware is still all crated up.
3.) That doctor sure does seem mad. Where does Bell work again?

Alright, this is the only item that doesn't actually have a hint of it's own. This is because, for obvious reasons both lore AND gameplay balance-wise, it's locked behind completing Fallout 3's main quest. At which point, purified water becomes MUCH more commonplace, so having it in your home becomes more convenience than game-breakingly overpowered.

The purification module is a miniaturized version of the tech your dad was working on. So go check our where Dad was. Besides, Bigsley's a busy man, he could use a hand!

You need wonderglue, a sledgehammer, and Hacksaws Tools (which you already have)

In the VAPL-58 Power station

Use the Sewer Waystation to gain access to the County Sewer Mainline (you can also enter from the grate near the Potomac, but this means you have to go through the whole mainline). Once you're in, find Gallo's hideout. There's a supply closet there, just near the tiny cross-path with all the traps. It has an average lock on the door. The valves are on top of the shelves.

You're looking for Lockers. Undamaged ones. Check the very back of the Super Duper mart, one of the rooms has rows of empty, unused lockers.

Exit Springvale garage through the garage doors. You should be facing Vault 101. Turn right - the house right next to the garage has a bedframe, half buried in rubble.
The fridge is in the porch of the mostly intact, but inaccessible house opposite Springvale school.
Now head back to the main crossroads of Springvale (the one with the megaton sign, near where you find the eyebot patrolling). Follow the road that leads to Vault 101. The oven is buried in the last house to your right (1st house on your left if you're heading INTO springvale from Vault 101).

Head into Springvale School basement. You need to break into the room with the ant in, which is behind a very hard locked door. The workbench is in the back left of this room.

Bigtown, Red's clinic, right next to the shelves.

Ryan Briggs's room, the one with the wonder-meat maker in. Look for the chemistry set and activate it.

Rivet City Hydroponics lab, on the table on the right of the room. You're looking for a small packet of seeds.
Soil can be found at Harold's feet in Oasis.

1.) Wheaton Armory location just gives you a holotape that gives you the next stage in the quest. You don't actually need to pick this up.
2.) Our Lady of Hope hospital. In a storage closet that's locked, with a Mr Handy inside.
3.) Robco Factory Mainframe, holotape on the table.

Bigsley's desk. (previously the reception of the Jefferson Gift shop area).