OK, turbines use a LOT of water, and are NOT very efficent

What you want (if you can get/build one) is a "corliss" type engine

Getting engines in the 3-5 HP range is NOT all that hard, in fact, I know folks who build them. The problem is the boilers. As Ironraven says, a LOT use coal, although getting wood boilers isn't that bad. You would PROBABLY want a vertical tube boiler. You will be highly dependant upon a reliable source of GOOD water, and learning all about boiler firing, water treatment, and the like

Boilers are complex enough that you have to realize that most industrial/commercial insurance companies came about to inspect/insure boilers