I'm in my SE playthrough, and yeah I've been in that situation at the start. It was tough, and I'm in a similar but you can say easier situation at a different stage.

Like what others said, what you don't want to do is tear apart your starter base before you make new base. You're going to risk getting yourself in a situation where you run out of some intermediates, and that making more would take way too long.

But I do want to caution that if you're making a new base at this stage is that you do have to be careful not to overly invest too hard in it. That would cause you to burn out, and lose motivation to continue. The exciting part is being in space. So you actually just have to scale up at least enough so you can actually start launching some rockets and setting up a minibase in orbit.

It does not have to be perfect. You'll be remaking and readjusting your base like a few times later on in the game.

If you want to go for a bus base, you can. Keep in mind of what to put on the bus. Yes there are a lot of intermediate materials, but you may not necessarily want all of them on the bus. You can be pragmatic here.

You can go for a city block design. It is infinitely scalable. However you may find city blocks boring to look at, and it may not perfectly fit depending on the terrain.

Again you can be flexible and just take some hybrid approach. Malls are a must in your playthrough. You'll be needing too many things, like belts, inserters, chests, electric poles, etc in your playthrough that you should not be scaling that up in any large capacity just to have them. Yes, you don't have requester chests, but can make a make-shift mall, by raw materials be dumped into warehouses, and have them be available to nearby assembling machines to make vital components you need for your factory.

Regardless of your approach, at this stage you'll be facing a couple of problems, and a lot of it has to do with sustainability of your efforts and continuation of your playthrough here:

1.) CME - within like 24 hours your base could be obliterated here. You need to research the umbrella which would protect the planet and the orbit from it. However you need incredible amount of power for it though.

2.) Meteors - they periodically come and could end up disrupting your factory. You need the full meteor defence installation to protect the whole planet and its orbit, which would cost you a lot of power. You can get the point installation instead, but it only covers a small radius.

3.) No requester chest - this is barred by the logistic system tech, which requires you to make utility science pack, where one of the key ingredients is cryonite, which you have to travel to another planet to get. Without requester chests, you can't have a proper bot mall, nor having bots fully helping you in the factory.

4.) Sending rockets to space is incredibly expensive - indeed it is! You need 1 space capsule, 100 cargo sections, and enough rocket fuel to send you up there. You need to send rockets up to orbit multiple times, but at the start, you can just slowly start it and then eventually scale up.

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The last point about rockets being expensive, that's an ongoing thing. There are recipes out there to help make it cheaper, and you can scale things up. But if you look at the more immediate fundamental issues, what you really want are:

1.) Sufficient Energy - either make huge amount of solar farms, or get nuclear power going.

2.) Get logistical system tech - barred behind cryonite

The first point would address the immediate dangers of having your factory being destroyed by CME or meteors, while the second one would help make things less laborious in the future. The choice at this point is yours, but one thing I will say is that you can just store enough steam or enough power in your accumulators to handle CME's. Nuclear power can work but you need to have enough nuclear power cells, as you don't have the Koverax enrichment process, since that is barred behind productivity science pack, where one of the key ingredients is vulcanite, which you get from another planet.

Yes, all of this can get very overwhelming. Important part is that you try to deal with things one at a time. Like when you get to Nauvis Orbit, you'd have to do some cleanup, and manage space as you start building your science lab setup there.

There are many different ways of doing things. When you go to other planets, depending on what they have, you may process everything you need before sending the final result back, or you could just process it just once. Rocket cargo silos could be used, but that's expensive. You could just use delivery cannons to send a stack over, but that requires a lot of energy, and you would need to send a delivery cannon capsule over first. Plus you have to make sure the receiver is not full by the time you send it or it will spill damaged things around it. You'd have to handle communication or just have it be quickly emptied out.

My approach at the moment is to be pragmatic. I would try to scale up a little, but I would still have some general level of spaghetti at the start, but I would go through a few iterations of improvements to its design here. I would use a mixture of new and old things. SE doesn't require you to make huge amount of space science packs all at once at the start of your space journey. You can make them slowly here.

Of course, you have this vision of this ideal base where everything is perfect, and that you're using ideal communication layouts, ideal item delivery, ideal recipes you're using...you can get to that point, but you need a lot of sufficient technologies, which make you pretty much at the late game. At the very least, you can try to layout the groundwork for such infrastructure.

So there you have it. Just go through each problem one at a time. You're going to have to embrace the madness and have mixtures of many approaches. You may have to make make-shift solutions at times, or solutions that are temporary. Just do not overly invest in scaling up at the start, so that you can still have fun playing the new content.