It took a bit of reading and praying, but nothing in this codebase actually requires the custom circuit boards or firmware. It runs just fine on Arduinos with matching processors (ATMega 328). Tested both an Arduino Uno R3 and an Arduino Pro Mini. Any generic LIN transceiver can be used on the appropriate pins.
I have the pinouts as:
rx1: D2 (receive from master via a 'slave' LIN transceiver)
tx1: D16
rx2: D15 (receive from your slave device via a 'master' LIN transceiver)
tx2: D4
Status LEDs on D7, D8, D9