Property Tax Millage Rates will vary between 15 and 22 depending on where in Spring Hill you're looking. For a good estimate, use a rate of 17 and that will put you in the ballpark. As far as insurance, this will vary as well depending on the age of the home, location, and features specific to that particular property.
HOA's & CDD's will vary depending on neighborhood - in the Spring Hill subdivisions, there are no HOA or CDD fees. But it's important to note that Spring Hill is a series of subdivisions, not a town or city and there are many neighborhoods WITHIN the Spring Hill Subdivisions that WILL have HOA & CDD Fees.
Overall, these are not "quick and easy" questions as there are many variables that can come into play. If you'd like, feel free to contact me at http://www.HernandoLuxuryHomes.com
and I'd be happy to get as specific as you'd like with regards to whatever properties in particular you find interesting.
I hope this was helpful!