I think this is approximately realistic. Though expectations should be clear about how this is not a fast network protocol.
Some enhancements we should eventually make to improve this usecase:
- A mode where a node will allow any BLE client to send via the mesh to some other user ID
- Yeah - an antenna like the moxon would be really ideal for this topology/range
- For the ‘repeater’ nodes you’ll want the repeater feature which should be in soonish (so that it uses minimal power and never goes to sleep)