My wife and I will be taking a Royal Caribbean cruise (Haiti, Puerto Rico, St Maarten, St Kitts) at the beginning of April. She has fatigue and mobility issues and I'm concerned about being totally out of contact if she wants to lay down while I go elsewhere on the ship. Not concerned about off-ship excursions as we'd be together. I'm considering walkie-talkies, but would be easiest if we could just use our phones to Text/SMS. Not worried about calls, just need to know if she needs me back in the room. I've seen that VZW has Cruise Pricing, but how does this work? Also, would we have to purchase the RC Zoom Data plan?