I have a CenturyLink DSL Router that currently has my printers hardwire connected to it. Behind the DSL Router, I have an Asus Router that is connect to another couple of Asus routers running as AiMesh nodes. I want the printers to be accessible by both the computers on my main LAN, as well as by iPhones / iPads that are connected to the guest network on the Asus Routers.
With my current setup, the computers on my main LAN can print just fine. The iPhones connected to my guest network can ping the printers, but they can't find them as AirPrint devices, as they are on a different subnet from the printers.
Note: Devices connected to the Asus guest network only have access to the internet. Not only are they isolated from the main LAN, they are also isolated from other devices on the guest network.