The router next to master socket, and ethernet running to am ethernet switch in a more convinent location is best solution.
CAT5e carrying an Ethernet signal will happily manage 100 Mbps over a 100 m run.
30 feet of twisted pair cable is unlikely to be an issue for an ADSL signal, but you never know until you try it in the RF environment in your home.
Only way to know is test each setup in your home.
Myself router at master, then Ethernet infrastructure cable to take the now IP network around the property