There’s a very old and variously attributed saying (no, Tanenbaum was not the first) that you can’t beat the bandwidth of a station wagon full of tapes. In a slight variation, a company in good old New Zealand has found a situation where the best bandwidth is provided by pigeons. It seems to me that some sort of fixed wireless, such as 802.11whatever with a high-gain directional antenna, would work just fine, but you have to hand it for them for finding a creative solution to their problem.