I wired it directly into the opener circuit to get POWER (24V), TRIGGER signal and DOOR CLOSED signal. Simple 4 wires coming out of the motor box going to the MIMOLITE. Works like a charm.
I had to follow some advice from a forum and use the "D_MimoLiteGarageDoor_invert.xml" in the device file under advanced settings. With that, door status is CORRECT if the input is pulled LOW when the door is down.