Theory of Operation

Raspbian configuration files are set so the Raspberry Pi (with dongles) boots as an access point with known ESSID, connected to a preselected wired or wireless upstream LAN.

/etc/network/interfaces.d/011_wlan0: configures static access point network.
/etc/network/interfaces.d/010_eth0: (router) configures upstream wired connection.
/etc/network/interfaces.d/012_wlan1: (repeater) configures upstream wifi client.
/etc/network/interfaces: Raspbian default configuration requires trimming.

/etc/{default,init.d}/hostapd: starts access point support at boot.
/etc/hostapd/hostapd.conf: configures access point.
/etc/dnsmasq.conf: configures dhcp and dns.
/etc/hosts.dnsmasq: Static ip addresses.
/usr/local/bin/hostapdstart: Start access point.
/etc/rc.local: Boot with access point.