In my personal play style, I like to start by building a small "standard" 1 or 2 belt per item bus. When I have most of everything researched I deconstruct my base and pack everything up onto a massive (farl - bulldozer mode) train and venture deep into the map. Like, a few screens away if your looking at the map screen zoomed all the way out. Then, I start looking for a large oil refinery with a nearby oil field. Yea they're rare, but once located, I use that as a starting point to begin laying the foundation for a mega base.
TLDR: You shouldn't need big refineries near the starting area since resources there are lame. Instead of reaching trains out to one of them, simply start your base near one
