Cabling simple sensors 5-20 ft from a uC - tips and gotchas; UTP vs STP cables
This is essentially what commercial alarm systems do: run power, ground, and a couple of signal wires to sensors and keypads.  They don't even run twisted pair, because they're not shipping data (except for the keypad, of course, and even then they rarely bother).

Alarm system sensors signal with a simple voltage divider.  When the sensor trips the voltage changes from its idle state, and the panel raises the alarm.







simulate this circuit &ndash; Schematic created using CircuitLab

I see no reason why you can't do the same with your switches and PIR (which, if it is a "normal" commercial PIR, should have an NO relay in it that it holds closed until the sensor trips (or loses power)).  The LDR can work the same way, but if you want to measure the light level you'll need to pay more attention than just looking for voltage excursions outside the idle range.

Just feed the signals into the toyduino's analog inputs.