Go to menuconfig, and select following things to enable network over USB for beagleboard. You won't need a wireless adapter or USB to ethernet adapter more. All will be over USB cable.
-> USB Support [y]
-> Inventra Highspeed Dual Role Controller (TI, ADI, ...) [y]
-> Driver Mode (Both host and peripheral: USB OTG (On The Go) Device
-> USB Gadget Support [y]
-> USB Gadget Drivers (Ethernet Gadget (with CDC Ethernet support) [y]
-> RNDIS support [y]