So after being informed on the Amateur Radio Exchange this isn't quite HAM/Amateur Radio, posting here.
So I'm, well, very new to general RF/radio in general other than basic WiFi, but I'm looking at the feasibility and cost of a long range (>200M between nodes, sometimes probably 500+M) in flat terrain, relatively low power (solar + 12V SLA, short term usage) and probably fairly low bandwidth needs (couple of hundred Kbps?), but bi-directional/fully shared. So in starting doing some searches/research, I came across SX1276 based module (https://www.adafruit.com/product/3072) that's relatively cheap, even if I need it for a few dozen or more nodes.
My concept is to use a fixed mesh, or star mesh topology as the distance between a centrally located node and the furthest away may be as much as 2+ km, possibly 3+. That's long term planning, my first attempt would likely be a handful of nodes perhaps 400-600m from a central point. The advantage of this area is flat as a pancake, although lots of varying height temporary structures, although the antennas would not be placed very high, 6-10 feet off the ground so they may or may not have perfectly clear line of sight.
Based on my reading of LoRaWan, it's really designed to be a central star network topology without much bi-directional communication, in general. And LoRa could, in theory, perhaps, do a mesh network but it'd need a non-trivial amount of software layered on top of the transceiver access code.
I did come across https://ieeexplore.ieee.org/document/8048465/ which is very interesting. In my naive reading of it, it implies that if you simply immediately re-transmit each packet once received (and ignore it once you've re-transmitted it) you essentially can flood a mesh network of LoRa devices reasonably efficiently despite collisions and such. I did see there's more to it than that with seeing to do offset concurrent transmission and other bits that I didn't get to. If that concept actually works reasonably well, it shouldn't be too difficult, in theory, to put a basic layer on top of a LoRa transceiver to spread data through a mesh (that doesn't actually know about each other really) in an Easy™ to implement fashion which spans several square kilometers.
So...disabuse me of this and show me how naive and unknowing I am and I should tuck my tail between my legs and run away :)