Yes. Once you unlock/own and/or gain the right to use a settlement workbench, you will automatically transfer any items you salvage and find in the wasteland there. And these will be available to use from any workbench you can access in the wasteland.
In regards to what to pick up: It really depends on what you want to do atm. Even if you don't plan to immediately build a settlement right after leaving the vault, consider building a small home/shack for your PC in Sanctuary Hills. Or claim the crafting station at the Red Rocket. Besides being the ideal location to store all the PA you'll find and craft, it also doubles as a base of operations. You can use Sanctuary and/or the Rocket as your home base HQ for all future trading settlement operations.
I'm currently turning the Sanctuary into a farming/crafting settlement to provide food and homes for trader NPCs. And the Rocket into a more industrial/advanced tech settlement to provide a base for making PAs, circuitry, electronics and the more advanced high tech. This means delaying doing any of the Minute Men quests ie. helping Preston G. Because if you help out the Militia Men faction, this will send many NPC settlers to your settlement. And this number DOES NOT include any random settlers you meet at campsites or on the road in the wasteland. The majority of non hostile settlers will attempt to travel to your settlements. So you'll also have to focus on building your turrents and other defenses early.
Since the crafting/workbench feature requires a high level of detail, I'd recommend that you invest in buying the game manual. Because it may be a while before someone uploads the game manual to the web. You can get a manual at Walmart now that the crazy midnight rush is over for $25 or so. Everything you need to know about what components go into building materials, armor, weapons etc. is listed there. But it may be more intuitive to use the ingame workshop menu. If you select the item (like a wall, door etc) that you wish to build, a list of picture icons for for the sub components making up the item you want to build will come up. You can use the tag feature to mark/highlight this item so that you'll better be able to salvage it while in the world.
BGS really helped out the crafters and builders when designing this feature. According to game manual (and verified from personal experience in game), when crafting in the workshop, you can also:
- setup a trade contract to have bulk junk shipments sent to your settlement! Traders will ship the components of stuff you need for your settlements directly to a settlement of your choice. Just have at least one other settlement you control then buy a shipment contract. The materials will be automatically delivered to your workshop/workstation. This will allow you to salvage for more rarer and exotic items that traders don't carry and/or do more quests/side quests. And yes, copper, steel, and fertilizer are the top 3 bulk items you'll need to build which traders thankfully ship to settlements.
- the game only uses the specific raw material in an item when building something. So if you salvaged a lead pencil (an EXCELLENT source of lead) or a telephone (an EXCELLENT source of Copper which you'll need tons of to build electronic circuits for your settlements), then the game will break the pencil down into it's wood and lead components. Or circuits, copper and fiberglass for the telephone. Now say you wanted to upgrade the RAD shielding on your PA which would require lead and some circuitry. The craft station would only use the pencil lead and telephone circuit materials for the armor upgrade. And it would store the unused raw material components of these 2 former items to the work bench. Which you would be able to access at any of your other settlements. So your scrap waste is minimized. Also if you don't want to use something you've constructed right away and don't care to destroy it, then you can also store it in the workbench for later.
- You can salvage most toys for their raw materials. However, these toys CANNOT be broken down into more base raw materials and can only be used for decor or resale:
- Any robot toy model you encounter
- all Buttercup toy horse models
Finally, on a partially related topic: stumbled across this special collectible at the East Boston prep school. Then looked it up in the guide which confirms it.
Spoiler Make sure you collect any overdue books you come across in the wasteland. These can be redeemed at book terminals at schools and libraries for book tokens. You can then use these tokens to earn very useful prizes and items!