This was just about the hardest part of the task. There are many choices, more alternatives, and no right or wrong answer. After a lot of looking and thinking I decided to use a roof tower on my detached garage.
While I have 12 acres of land, most of it is deep ravines and useless for towers and antennae. I have a good sized front lawn but nothing useable on the back. My detached garage is the high point of my property with deep sloping ground on three sides. I planned to put up a taller tower later but felt the urge to get some kind of directional antenna up as soon as possible.
The garage is about 20' tall at the peak. I chose a Glen Martin 17 1/2 foot tall roof mounted tower. It is rated to more than handle the wind load of the SteppIR 3 element beam in 87 MPH winds. And the price was very reasonable. So away we go.
The tower came in pieces and I had the opportunity to stick build my tower. That was a fun project.