It's difficult to determine how much range you're going to get without an understanding of your geography, obstructions, local interference, etc. The miniscule signals that Part 15 transmitters put out can be dwarfed by any number of environmental factors. You have to experiment.
Plus, you should understand that the range also depends on the receiving radio at the other end, with its antenna. Car radios (with their outside antennas) are best, but you have to be in your car to listen. Most people in their homes have cheaper, less sensitive radios (and the low power signal is further degraded reaching the radio in a home, unless they have an outside antenna, which is doubtful). But the biggest factor that works against range with cheap radios is their poor selectivity and adjacent channel rejection - strong signals close to yours will bleed over and obliterate that tiny signal. A one mile range with a good signal in a car can go down to several blocks on home radios.
I'd go at first with a ready made, turnkey system such as the Talking House or the ChezRadio procaster. Once you've gotten your feet wet, so to speak, and see if you can get anywhere close to the range you want, you can experiment with kits and different types of antennas (which bring their own sets of problems to the table - if you get horrible range, you won't know where to start).