Technically, you can only cancel your contract if you don't get service in your front lawn. Cell phones aren't designed to work inside, and Verizon will tell you that when you call. In fact, the CEO of Verizon was quoted as saying "Why in the world would you think your (cell) phone would work in your house? The customer has come to expect so much." (
Source)
If you get coverage outside your home, but not inside, you may have to really fight for a cancellation.
Your best bet is to call another carrier and ask them if they'll give you a "switching credit" on top of the "new customer" credits since you're still under contract with Verizon. Some companies will pay your early termination fees with another carrier to get you into a contract with them.
You can also wait for a material change to your Verizon contract (like a text message increase) and then cancel the contract that way. Both parties have to agree to contract changes, so if they try to change your contract in any way that will materially affect you, then you can back out of the contract. See the
Consumerist for more details on how to escape Verizon contracts.
-Dan