Not only no internet but you are limited by the laws of physics if you tried to use WiFi. The metal building is a Faraday cage.
In short, you aren't new to networking but I fear you need to refresh your knowledge of physics.
-> For now until you brush up, continue with your current way of doing this work.
Ok so here's the situation, we have a mobile office that I need to set up a wifi network. In the mobile work environment there will be no internet (sometimes not evan a cell signal!). There will be 3 wireless computers & 1-2 wired printers in the mobile office, and the need to "broadcast" the signal to a wireless laptop and a couple iphones/ipads in the field. Sometimes the broadcast ability will be line-of-site around 1/2mi but most of the time it will be out of sight, inside a brick or metal building. Devices in the field need to transmit data back to computers in the mobile office. I'm not completely network illiterate (I can read and follow instructions) but I'm not really sure what hardware I need. All new laptops with 802.11ac, new printers with high speed ethernet, iphone 7+ all good for 802.11ac. Thanks!

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