The above is what you have to do for two scenarios:
The Iro cannot be located near a WiFi signal - i.e. an Iro's out in a weatherproof box somewhere on the property, centrally located to the first 16 zones. And then another Iro's somewhere else out on the property, centrally located to the next 16 zones. Etc. You may even have to implement some kind of small solar charged electricity providing station. Think small or few municipal parks here.
The Iro is located near a secured WiFi signal that's not available to the Iro. I.e. the building owner versus tenant situation written about above.
We encounter the second situation occasionally with networked thermostats that we install. We used FreedomPop with good success, as written above too. Now, though, the Sprint 3G network is going away. Thus, you need to be sure that you're using an offering from FreedomPop that's 4G.
What would be nice is if the Iro would have an Ethernet connection too. Then the Iro could be viewed as a POS device, and you could take advantage of all of the cellular offerings for POS equipment.