* Cantenna/laser link to a house some blocks away to avoid local WAN link disruption
* For less performance-intense networks, remove the physical impediments: 2 routers, each with 1 APC, connected to 2 separate power circuits, connected to 2 WAN links, providing 2 radios each. No switch to go down or cables to trip over, redundancy of access point, redundancy of frequency/radio, redundancy of WAN link, redundancy of power. Hardware-wise this is pretty cheap and still highly available. If the routers are cheap, use a hardware watchdog.
* Cantenna/laser link to a house some blocks away to avoid local WAN link disruption
* For less performance-intense networks, remove the physical impediments: 2 routers, each with 1 APC, connected to 2 separate power circuits, connected to 2 WAN links, providing 2 radios each. No switch to go down or cables to trip over, redundancy of access point, redundancy of frequency/radio, redundancy of WAN link, redundancy of power. Hardware-wise this is pretty cheap and still highly available. If the routers are cheap, use a hardware watchdog.