There are many scrappable junk items that can be used whole for other purposes, for instance for specific quests or as a crafting ingredient:
Used for Quests (repeatable quests italicized)
- A Biometric Scanner and a Military-Grade Circuit Board are required for the main quest The Molecular Level.
- 4 High-Powered Magnets are needed for the Brotherhood of Steel quest Liberty Reprimed, but they are provided in the Boston Airport workshop.
- Yellow and Blue paint cans - Abbot (Diamond City)
- Bloatfly Gland - Doctor Duff (Diamond City)
- Bag of Fertilizer - Priscilla Penske (Vault 81)
- Adjustable Wrench, Ball-peen Hammer, Combination Wrench, Hammer, Screwdriver, Wrench - Calvin (Vault 81)
- Anti-Freeze Bottle, Gas Canister (for Reactor Coolant) - Proctor Ingram (Prydwen)
Used as Crafting Ingredients
- Abraxo Cleaner - Mentats, Mind Cloud Syringe
- Anti-Freeze Bottle - Berry Mentats, Berserk Syringe, Yellow Belly Syringe
- Baseball - Baseball Grenade
- Bloatfly Gland - Bloatfly Larva Syringe
- Bloodsac - Skeeto Spit
- Brahmin Skull - Mounted Brahmin Skull
- Coffee Tin - Slocum's BuzzBites
- Molerat Teeth - Mounted Molerat Skull
- Pencil - Endangerol Syringe
- Radscropion Stinger - Radscorpion Venom Syringe
- Skull - Spiked Pole
The doctor in Diamond City was the first one I ran into in my first couple playthroughs. There are a few doctors you could reasonably get to beforehand without going way out of your way, but they're neither a lot sooner nor much easier to get to, so you aren't missing out by just going ahead and continuing to Diamond City instead.
Bethany
There's a doctor in a shack surrounded by radiation west of ArcJet Systems. The doctor is a ghoul, so the radiation doesn't bother her. If you already have enough radiation resistance, perhaps from the power armor in Concord, then this doctor might be worth visiting. Unfortunately, there's no fast travel waypoint.
Patricia Montgomery
There's a doctor in Covenant. Covenant is pretty easy to reach if you go east a bit. You'll have to go through the SAFE test at the door, and she may turn hostile depending on your choices in Human Error.
Rachel
There's a doctor you can see in Vault 81. I often go by Vault 81 on my way to Diamond City, but it's not very far away and you may not even need to fight anything between the two locations, so you're not really gaining much by going here first.
Furthermore, you have to either pass a charisma check or donate three fusion cores to gain entrance. The check isn't too hard, especially if you don't mind loading a few times. You should be able to get past it with some Charisma gear and/or some temporary buffs.
Doc Weathers
There is a traveling doctor. I usually run into Weathers at Bunker Hill, in the stall next to Deb. This stall rotates between the various traveling merchants. Sometimes Trashcan Carla is there. Weathers can also be found traveling around the northern part of the map. The wiki article says he starts at County Crossing, near the National Guard Training Yard.
If you spread east before going down to Diamond City, you'll probably run into Weathers at some point. Bunker Hill is a fairly easy to reach early hub. You could just as easily get to Diamond City though, if you decided to go that direction instead.
Make Your Own
You'll probably get to Diamond City before Level 14, but maybe not, depending on play style. At level 14, you can get Local Leader 2. This, combined with Medic 1, allows you to build a pharmacy in your settlement. You can assign a settler here, and get all the services provided by a normal doctor.
Best Answer
There is a list of all names (Given names and Surnames)* that Codsworth recognises, without using additional mods.
They are, however not separated, merely ordered alphabetically. My bet is that names that are put in the "first name slot" and "last name slot" will determine whether or not he calls you "Adam", or "Mr/Mrs. Adams".
Additionally, I don't believe that there is a "middle name slot" that is recognised, and could potentially throw the whole thing out, resulting in Codsworth simply referring to you as "Sir" or "Ma'am", and determiners like "the" would be a cause of this.
*NSFW Warning