best practices for robust sensor input

[golf32]

I have a device which needs to read a float sensor which is installed possibly 100 feet away across a field. What's the best practice for designing a robust input protection/sensing circuit for this? I've attached a screenshot of a previous revision. In the new revision I don't have access to a 12v rail, instead only a 24v rail and an isolated 5v rail.

I suppose I should add a polyfuse to the rail so it doesn't cripple the rest of the system in case of a short.
Do you guys think the transistor is necessary for a microcontroller input? Originally it was moreso for level shifting the 12v signal.

edit: forgot to attach schematic...