Since you're staying in TX and won't be moving around, then your PO arrangement should work ok, and everything else should be pretty much the same as moving from one house to another within the state. About the only thing I can think of that you'll need to do differently would be getting full-timers insurance on your RV since you won't have the homeowners coverage that extends to your RV anymore. With a PO box address you may have to use the park street address for some things, adding the PO box for mail delivery. Most accounts that require a physical address also accept a separate mailing address.
