ROAMING is your easiest way out of a Sprint contract ETF free. You see Sprint pays for its customers to roam onto other carriers towers. The more you roam the more it cost Sprint they will eventually send you a letter or give you a call literally asking you to leave and find another carrier. HOFO has many threads on how to force your phone to roam but that doesn't seem like an issue for you as you already roam constantly. Here is the TOS on roaming, this is directly from Sprint.
Off-network Roaming: The primary use of your Device must be for domestic purposes within the Sprint-owned network. Domestic means use in the 50 United States and U.S. Territories (except Guam). Sprint reserves the right, without notice, to deny, terminate, modify, disconnect or suspend service if off-network usage in a month exceeds: (1) voice: 800 min. or a majority of minutes; or (2) data: 300 megabytes or a majority of kilobytes. The display on your device may not always be on and will not indicate whether you will incur roaming charges. You can monitor usage online through My Account. Roaming is not available with single-band phones, or to customers who reside or whose primary use is outside an area covered by the Nationwide Sprint Network. Sprint may limit or terminate service if you move outside of the Sprint owned-network.
EDIT: Not sure which plan your on but make sure its included in your plan because you don't want to rack up "roaming charges". All current plans include roaming at no additional cost, so if you have any of those you should be fine.