I use a non cell iPad with my precision planter, it just uploads the data to the server whenever I bring it inside.  Once the data has (automatically) uploaded to the server, anyone with the password can log in and look at it.  In fact, I'm usually using my brother's Ipad in the tractor since my kids always want mine during planting time and it works just fine for us.  The only problem is I can't get real-time satellite backgrounds or if something were to happen to the iPad I would lose all information since the last upload.