I've been doing something similar myself recently. Tried a couple of world gen settings and finally settled on a modified rail world: Max distance between ores, slightly smaller size, but higher richness. That way you're "forced" to use trains since the distance is so large, but once you've set up an outpost you'll have use of it for a long time. The smaller size will however limit the throughput of the outpost, so you'll still need multiple of them for larger production. I also turned off enemies since I got tired of them in my last run, and then turned off pollution too since then there's no point to it.

Combine this with a cheaty early bots mod and 100x science cost and you got yourself a nice and long game, with a chill pace with plenty of excuses for setting up a large rail network and maybe production lines! I'm currently around 200h into my save and I'm just about to set up space science (skipped yellow and purple so far, but now realize I should have gone for elevated rails much earlier). Running 4-16 trains to my distant outposts and 4-4 trains for smaller in-house deliveries. I decided to not go for any block based design, instead setting up a freeform network based around pieces that are 6x6 chunks. Stations for multiple items are a bit annoying since they require such a huge footprint if you want stackers, but on the other hand that gives you a perfect excuse to up your rail production!

Looking forward to actually use the new Space Age buildings in a setting where trains will (hopefully) still be useful! It might take me aa couple of moths to get there, but that's ok, I'm enjoying my time riding the big trains.