We haven't done this before, but have a road hand who wants to go to another precinct. He's a good employee, both bosses are OK with it.

What policies - if any - do you have in place for this? Does liability for comp time go with the employee, or is it somehow kept with the initial department? What about other departments?

Any policies appreciated,

If the employer (presumably the county) remains the same, and all retirement credits, vacation time, seniority grade/step remain the same, I do not see any basis at all for the comp time not to go with the employee, as it is personal to the employee. Though the precinct changes, the employer is still the same (same EIN), pay is still handled through the auditor / treasurer. No written policy here - likely because it seems pretty straight forward.

Do you offer a post to employees first? Concurrent with public posting? Is there an "edge" for current employees?

We don't do seniority or "step", nor do we have any human resources types. Is it encouraged only between jobs with similar skills? Or may a deputy decide to apply for road hand?