I think that the usual system, at least it is what I have done, is to wire both X Axis switches in series - both Y Axis switches in series and both Z Axis switches in series etc.(for normally closed contact switches). Each pair of switches then has its own input to the parallel port.
For homing - Mach homes in a set direction, and order of axis, until it finds the switch which will act as both 'home' and 'limit' for that axis. Mach then homes the next axis the same way etc etc.
The 5Volt needs to come from your 4 axis interface or breakout board, not from the parallel port.
Hope this helps,
Tweakie.