Did some testing with good old Star Commander. So far it works fine (no parallel cable yet), but the passive heatsink on the pentium cpu was not sufficient. I removed the passive heatsink and added a heatsinkfan. Now the wires are in the way when closing the case. I'll have to figure out a way to tidy up the wires, which may mean some extra work...
Won't be finished tonight, but happy to see everything working closed up! With any luck I'll be using nibtools with a parallel cable by tomorrow night.