One thing nobody has asked or mentioned... You say you will be full-timing for three months. Stationary for the full three months? If so, I would check with the campground you will be staying in, provided it is a private campground, to see if they have Telco hookups. If they do, I would look into DSL service from the local telephone company. I do that where we spend our winters, the phone line is easily routed through the slide seal, Connected to a wireless router (create a secure SSID) and will then provide the same "homestyle" service that you may already be accustomed to. I have a wireless DSL router that is a duplicate of my S&B router...when it starts broadcasting, all of our devices automatically connect seamlessly. Broadcast data plans are inherently costly, subject to throttling and your cap may sneak up on you. DSL has a fixed cost, usually cheaper when you consider there is usually no caps or throttling involved.
Just another idea to consider if you are going to be stationary for those three months while you finish your posting. I'm guessing from your handle and location that you are Coast Guard, I had an uncle that was a lifer and was a radar specialist...thank you for your service. Most people forget what an integral piece of security the USCG is for our maritime borders.