I'm using 3 Linksys routers (as dumb AP devices) loaded with DD-WRT for the last …. many years !
Version : Firmware: DD-WRT v24-sp2 (10/10/09) std
My wifi network is hooked up to pfSense, OPT2, using 192.168.2.1/24.
AP1 has IP 1912.168.2.2
AP2 has IP 1912.168.2.3
AP3 has IP 1912.168.2.4
For all AP's :
Subnet Mask : 255.255.255.0
Gateway : 192.168.2.1
Local DNS : 192.168.2.1
Local DHCP server : disabled.
WAN Connection Type : disabled.
All my AP's are hooked up to pfSense using a central switch, but daisy chaining from OPT1 to AP1 to AP2 etc is also possible (I never use the WAN port, even when it is declared as another LAN port).