I need some advice/critique on this factory plan.

[open rapids]

I've made a plan for a new factory that should hopefully get me past blue science and into logistics bots but it's my biggest project yet and my first time dabbling in oil processing and train networking. Because of that I've tried limiting the amount of trains I use but looking at it now I think it'd be better to use trains for most of the raw materials. The current plan looks like this (Dark red lines are belts and white lines are trains).

My main question is how should I go about mining and transporting the materials into smelter stacks so that I can have (preferably multiple) expandable lines of each resource on my main bus as the main factory is intended to be a bus of base materials running through the middle with small factories on the sides which pull off of the bus.
An issue I ran into with my old base was that I only had one belt of each material and that combined with the bus's incapability to be expanded caused me to be unable to add any more iron/steel consuming factories.

The only mods I have installed are TheLab and a skin mod for my character.

Oh I should also add that while I haven't done true oil processing I did make a small plastic setup earlier so I have a handful of red circuits for stack inserters.

[harsh flare]

Nice that you're planning it out, if that main factory area goal is to launch a rocket I'd give yourself a bit more space

Trains are easiest when they are only carrying one product, so keep that in mind. Also recommend to build two parallel single direction tracks

To enable expansion of the bus, it is usually recommended to only build on one side of it

[open rapids]

Thank you, I had already planned to turn the main factory up towards the desert if I ran out of space and I didn't think of only placing factories on one side.
Although one big problem I'm having is the train fuel, is it better to just pull fuel from the furnace stacks they're delivering to or should they have their own mine?

[harsh flare]

Doesn't really matter with the fuel, set it up however you like.

I normally rough in a belt for a couple of trains until I get logistics up and running then use requester chests

Or if I really can't be bothered I'll manually dump a bunch of fuel in a normal chest

[open rapids]

Tbh with how few trains I'm using and they're relatively close proximity to the base being lazy and hand feeding a chest fuel is probably better >.>

[harsh flare]

Yeah I normally well and truly have robots running by the time my train goes through a chest of solid fuel

[small rose]

I'd move "oil material" up closer to the main factory so that they be connected via belts. This avoids the need for a second train.

I'd also like to point out that some oil products require a small amount of copper, so moving oil materials closer to the copper mines will also be useful.

Finally I would also include oil refining in that section and only ship crude oil with the train. With your current plan, you will struggle immensely when you get advanced oil processing due to having to balance the 3 oils despite their production and consumption being so far away from each other AND made more difficult by having a mixed train between them. To run smoothly, advanced oil processing needs feedback on what is being consumed so that it can adjust the amount of cracking. If a train is inbetween the oil processing and the oil consumption, this feedback will be indirect at best, completely absent at worst. It might be possible to do, but it will be a pain.

TLDR: just put everything right next to your main factory so that everything can be connected by shortish belts. The only thing the train should transport is crude oil.

For fuel, just feed your train coal at the main base where you already have coal. Trains do not consume much; it will have very little impact on your overall ressources.

[river cargo]

My advice is you shouldn't overthink it at this scale. you're going to be rebuilding a lot no matter how much you plan up front

a wise man once said if you can't make it perfect, make it adjustable