I was forced to cave and tap a third iron node (and set up rails), I was getting to ~2 red belts of iron which could not sustain the base.
At least I was able to get logistics network before it became untenable, so I could bot mall all the stuff I needed.
Next is getting nuclear power researched - it's too useful for powering nauvis, getting nuclear fuel for trains, and even getting the better steam turbines for when I make it to vulcanus. I'm also trying to trickle in enough purple science to get both beacons and green assemblers (that is part of why my iron/steel went to 0).
I still think I need to get through vulcanus and fulgora before trying out the new planets. I would think about doing gleba as well (biolabs are broken), but I want to try the planets sooner rather than later