I just started a new run with this (loving it btw, likely going to be how I start every game from now on), and I now have Moshine, Igrys, and Corrundum in between me and Vulcanus. Problem is, to unlock any of those three planets, I need metallurgical science. So I'm stuck behind a blockade of planets, and I'll have to either cheat some metallurgic science in, change the science requirements, or teleport my ship past it.

TLDR: Any way you could change the space route logic to force Vulcanus to be connected to the stranded location, regardless of modded planets?

Mh interesting, the connection is created by this mod so it's weird that it disappears with other mods

I took another scroll through my modlist and found Redrawn Space Connections, which is required for several planet mods. I feel like that might be the culprit, in which case I think it would probably just be making a patch so that mod ignores this one, but I don't know that much about modding yet so I have no idea. For now I just removed Igrys and Corrundum and got the original path back.