As I get more settlements, I find it increasingly difficult to build the adequate amount of defenses (among other necessities) for each one. I know that I can fast travel to my main settlement and grab the junk items I'd need, but that seems like too much effort (and last time I did just that, the settlement in question got attacked while I was gathering supplies, reminding me of the urgency of the matter). I have yet to get enough spare settlers in my settlements to create supply lines, with preference on sending provisioners to the nearest settlement instead of making them hike to the other end of the Commonwealth.

Has anyone else had similar struggles with trying to get enough materials to build defenses and such at their settlements? Or any good strategies to keep most settlements supplied? For me, I'm struggling with any settlement not clustered in the northwest corner.

First of all: Local Leader. Set up trade routes between settlements and all your workbenches becomes one and whatever you have in one settlement is available to all.

Secondly: Strong Back. Maxed out, you can fast travel when overloaded. So you can clear Corvega and loot everything. Then I like to travel to a vendor and trade all the guns and armour for shipments and junk. Then I take it all back and dump the junk in the workbench.

Thirdly: Scrapper. Level two and you can break guns down into lots of useful components and recover things like crystal and fiber optics that can otherwise be hard to find.

Fourthly: A couple of light machinegun turrets when you set the place up can keep things settled until you get a chance to do it all properly.

Lastly: if you're short on just one item, it can be fun to walk to the nearest visible structure and see what you can scavenge. I needed ceramics for the Castle one time and ended up discovering Gwynneth Resaurant and clearing out the cups and plates.

That's my approach anyway. I actually ran out of fiber optics last night. I'd been splurging on laser turrets at the time. First time I'd run short of something in a long time.

I already have Local Leader and Strong Back, the issue is being able to have the resources to add more settlers to my settlements so that I can have spare people to send to other settlements for supply lines. What good is more settlers if I can't give enough defense, beds, etc.? Sanctuary, Red Rocket, Sunshine Tidings Coop, and Abernathy Farm (and maybe Starlight Drive-In...I don't remember) are really the only settlements I have linked up, and even then I find myself low on supplies sometimes.

Nothing strange here...
You're just like everyone else!
And I've been doing all this stuff with no Strong Back, no Local Leader, no Scrapper etc. LoL
I find certain of my settlements (the ones with beacons) are overrun with people.
Like 12 people and 8 beds, y'know?
So you've gotta send four settlers to other locations where you wish you had more people.
Other that that? Hey, tough to be a Minuteman, heheh...
But it sounds like you're doing great!

Ah, they can rough it for a day or two until you're ready to get things set up

What you can do is set up a small settlement and use it as a recruiting center. Ones with low population grow fast, so you can find a settlement with three people, set one of them to have a new home, and then immediately assign them to the supply line.

The small settlement quickly recoups the population, the new one gets a supply line and you have the resources there to build,

Anyway, that's how I do it. I appreciate it might not suit your play style,

I set my second or third settler as a provisioner. More important than farming when you're beginning a new settlement.