If you are willing to run the wires, go for it.
However, a tweak to your plan:
You can't really run 3V across your 'distribution system' as when the power goes from source to load it will drop voltage really quickly. You would have to run a higher voltage, at least 12V, preferably higher, and add a voltage regulator at each sensor to drop the 'high voltage' down to 3V. This will make up for the voltage drop along long runs of wire.