The higher on the tower you go, the longer the cable, which adds to the expense and increases the needed transmitter power due to the extra loss. The most cost effective solution give you line of site or near line of site to areas of population within 8 to 10 miles. If you choose a roof top for a tower site, you may have to address of interference to neighbors televisions and stereos. Even a small transmitter can cause significant interference. It is also wise to avoid towers that carry cable TV antennas.
Interference is likely, and can be expensive to solve.
This would be most appropriate for a LP-100 station. The point of getting up in the air is to have line of sight. From wherever your antenna is mounted you should be able to see every place you plan to cover. If you do not have this, your signal will be shadowed, and will suffer from multipath and low received signal level. The total area shown is about 13 miles wide and a LP-100 station should cover half.